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LABORATORY  MANUAL 

OF 

DYEING 

AND 

TEXTILE  CHEMISTRY 


BY 

J.  MERRITT  MATTHEWS,  PH.D. 


FIRST  EDITION 

FIRST   THOUSAND 


£^BI*Ai^> 

OF  THE 

UNIVERSITY 

OF 


NEW  YORK 

JOHN    WILEY   &   SONS 

LONDON:  CHAPMAN  &  HALL,  LIMITED 
1909 


Main  Lib. 

,.  lab. 


XP 

«o$> 

x 

A 


Copyright,  1909, 

BY 
].  MERRITT  MATTHEWS 


Stanhope  iprcss 

P.    H.   GILSON     COMPANY 
BOSTOM.     U.S.A. 


PREFACE. 


THIS  volume  is  designed  with  the  purpose  of  meeting  the 
demand  for  a  text-book  on  the  subject  of  textile  dyeing  and 
chemistry.  The  method  of  presentation  and  the  subject  matter 
herein  contained  have  been  the  outcome  of  a  number  of  years 
of  teaching  on  the  part  of  the  author.  Care  has  been  taken  to 
avoid  a  too  purely  scientific  generalization,  else  as  a  text-book 
it  would  lose  its  main  value.  The  subject  treated  is  a  technical 
one,  and  an  endeavor  has  been  made  to  present  it  in  a  technical 
manner;  that  is  to  say,  definite  facts  have  been  presented  in  a 
definite  form.  For  this  purpose,  the  experimental  method  has 
been  adopted,  further  elucidation  being  given  in  additional  notes 
as  succinctly  expressed  as  possible.  The  insertion  of  quiz  ques- 
tions has  also  been  carried  out  in  order  to  stir  up  the  thought 
of  the  student  after  he  has  performed  the  manual  experiment. 

This  book  is  intended  as  an  elementary  manual  for  the  students 
who  are  primarily  to  be  found  in  the  various  textile  schools  and 
in  institutions  where  the  many  branches  of  technical  chemistry 
are  taught.  It  is  hoped  that  it  will  be  of  some  value  to  both  the 
student  and  the  teacher  interested  in  this  line  of  instruction.  It 
is  primarily  a  laboratory  manual  or  guide,  and  is  intended  to  direct 
and  supplement  the  lectures  of  the  teacher,  and  should  be  used  in 
conjunction  with  the  more  general  treatises  on  the  subject. 

The  subject  matter  is  divided  in  such  a  manner  as  to  provide 
a  course  of  instruction  for  one  complete  college  year,  each  section 
corresponding  to  a  weekly  apportionment  of  study.  The  experi- 
mental part  will  require  from  eight  to  twelve  hours  of  laboratory 
practice  each  week;  though  sufficient  experiments  have  been 
given  to  allow  the  teacher  considerable  latitude  as  far  as  selection 
of  material  and  length  of  laboratory  practice  are  concerned. 

J.  MERRITT  MATTHEWS. 
TAUNTON,  MASS.,  December,  1908. 


184419 


CONTENTS. 


INTRODUCTORY. 

PAGE 

Apparatus  Required I 

SECTION  I.  —  CHEMICAL  STUDY  OF  THE  FIBRES. 
EXP. 

1  Action  of  Acids  on  Wool  and  Cotton 5 

2  Action  of  Organic  Acids  on  Cotton 6 

3  Action  of  Alkalies 6 

4  Action  of  Metallic  Salts 6 

5  Action  of  Bleaching  Powder 7 

Notes 7 

Samples  (1-21) 10 

Quiz  i  (1-26) 10 

SECTION  II.  —  SCOURING  THE  TEXTILE  FIBRES. 

6  Scouring  Raw  Wool  by  the  Emulsion  Process 12 

7  Use  of  Potash  in  Scouring  Wool ; 12 

8  Effect  of  High  Temperatures  in  Scouring 12 

9  Effect  of  Using  Excessive  Alkali  in  Scouring  Raw  Wool 12 

10  Scouring  Woolen  Yarn  by  the  Usual  Method 13 

11  Scouring  Woolen  Yarn  Containing  Iron 13 

12  Scouring  Cotton  with  Caustic  Soda 13 

13  Scouring  Cotton  with  Soda  Ash 13 

14  Scouring  Cotton  with  Soap 14 

15  Scouring  Cotton  with  Fankhausine 14 

16  Scouring  Raw  Silk 14 

Notes 15 

Samples  (22-39) 24 

Quiz  2  (27-57) 25 

SECTION  III.  —  BLEACHING  OF  WOOL. 

17  Bleaching  Wool  by  Tinting 28 

18  Bleaching  Wool  with  Sulphurous  Acid  Gas 28 

19  Bleaching  Wool  with  Sodium  Bisulphite 28 

20  Bleaching  Wool  with  Sodium  Peroxide 29 

21  Bleaching  Wool  with  Potassium  Permanganate 30 

Notes 30 

Samples  (40-51) 37 

Quiz  3  (58-81) 38 

v 


vi  CONTENTS. 


SECTION  IV.  —  BLEACHING  OF  COTTON. 

EXP.  PAGE 

22  Bleaching  Cotton  with  Chloride  of  Lime 40 

23  Use  of  "Anti-Chlor"  for  Removing  Chlorine  in  Bleaching 40 

24  Bleaching  Loose  Cotton  for  Absorbent  Purposes 41 

25  Tinting  and  Softening  of  Bleached  Cotton 41 

26  Use  of  Acetic  Acid  in  Bleaching 42 

27  Use  of  Lime  Boil  in  Bleaching  Cotton 42 

28  Use  of  Sodium  Hypochlorite 43 

29  Comparison  of  the  Use  of  Sulphuric  and  Hydrochloric  Acids  in  Bleaching 

Cotton 43 

30  Use  of  Chlorozone 43 

Notes 44 

Samples  (52-67) 53 

Quiz  4  (82-107) 53 


SECTION  V.  —  CLASSIFICATION  OF  DYES. 

31  Action  of  Acid  Dyes 56 

32  Action  of  Basic  Dyes 56 

33  Action  of  Substantive  Dyes 56 

34  Action  of  Mordant  Dyes 57 

35  Action  of  Pigment  Dyes 57 

Notes 58 

Samples  (68-86) 66 

Quiz  5  (108-130) 67 

SECTION  VI.  —  APPLICATION  OF  ACID  DYES. 

36  General  Method  of  Dyeing  Acid  Colors  on  Wool 69 

37  Showing  the  Use  of  Glaubersalt  in  the  Dye-bath 69 

38  Showing  the  Influence  of  the  Amount  of  Acid  in  Dyeing  with  Acid  Colors .  .  70 

39  Showing  the  Exhaustion  of  the  Dye-bath 70 

40  Dyeing  Acid  Dyes  in  a  Neutral  Bath 70 

41  Dyeing  of  Alkali  Blue 71 

Notes 72 

Samples  (87-101) 82 

Quiz  6  (131-164) 82 

SECTION  VII.  —  APPLICATION  OF  Aero  DYES. 

42  Dyeing  Acid  Dyes  on  Acidified  Wool 85 

43  After-treatment  of  an  Acid  Dye  with  Chrome 85 

44  Use  of  Acetic  Acid  in  Dyeing  Acid  Colors 86 

45  Use  of  a  Chromotrop  Dye 86 

46  Use  of  Phthalein  Dyes 87 


CONTENTS.  Vll 

EXP.  PAGE 

47  General  Method  of  Dyeing  Acid  Dyes  on  Cotton 87 

48  Dyeing  in  a  Neutral  Salt  Bath 88 

49  Use  of  "Blue  Mordant" 88 

50  Use  of  Sodium  Stannate  Mordant 88 

51  Dyeing  Silk  with  Acid  Dyes 88 

52  Use  of  Acetic  Acid  in  Dyeing  Silk 89 

53  Use  of  Boiled-off  Liquor  in  Dyeing  Silk 89 

Notes 90 

Samples  (102-123) 95 

Quiz  7  (165-193) 96 


SECTION  VIII.  —  REPRESENTATIVE  ACID  DYES. 

54  Representative  Acid  Dyes  on  Wool f 98 

55  Representative  Acid  Dyes  on  Cotton 98 

56  Representative  Acid  Dyes  on  Silk 99 

Notes 99 

Samples  (124-151) 105 

Quiz  8  (194-219) 106 


SECTION  IX.  —  TESTING  THE  FASTNESS  OF  COLORS. 

57  Fastness  to  Light 108 

58  Fastness  to  Washing 108 

59  Fastness  to  Fulling  or  Milling 109 

60  Fastness  to  Water 109 

61  Fastness  to  Perspiration 109 

62  Fastness  to  Carbonizing. no 

63  Fastness  to  Cross-Dyeing no 

64  Fastness  to  Stoving no 

65  Fastness  to  Chloring in 

66  Fastness  to  Crocking  or  Rubbing in 

Tabulation  of  Results  of  Tests 112 

Samples  (152-201) 115 

Quiz  9  (220-256) 115 


SECTION  X.  —  APPLICATION  OF  BASIC  DYES  TO  WOOL  AND  SILK. 

67  General  Method  of  Applying  Basic  Dyes  to  Wool 118 

68  Showing  the  Effect  of  Hard  Water  on  Basic  Dyes 118 

69  Showing  the  Greater  Coloring  Power  of  Basic  Dyes  over  Acid  Dyes 119 

70  Use  of  a  Neutral  Bath 119 

71  Dyeing  Silk  with  Basic  Colors 119 

72  Dyeing  Silk  in  a  Neutral  Soap  Bath 119 


Viii  CONTENTS. 

EXP.  PAGE 

73   After-treatment  of  Basic  Dyes  on  Silk  with  Tannin   120 

Notes 1 20 

Samples  (202-214) 122 

Quiz  10  (257-280) 123 


SECTION  XI.  —  BASIC  DYES  ON  COTTON. 

74  General  Method  of  Dyeing 1 24 

75  Fixing  Tannin  on  Cotton  with  Tartar  Emetic 125 

76  Fixing  Tannin  with  Copperas 126 

77  Use  of  Other  Agents  in  Dyeing  Basic  Dyes 126 

78  Dyeing  Basic  Colors  in  One  Bath 127 

79  Use  of  the  Janus  Dyes 127 

Notes 127 

Samples  (215-226) 131 

Quiz  ii  (281-326) 131 

SECTION  XII.  —  REPRESENTATIVE  BASIC  DYES. 

80  Principal  Basic  Dyes  on  Cotton 135 

81  Principal  Basic  Dyes  on  Silk 136 

Notes " 136 

Samples  (227-246) 145 

Quiz  12  (327-368) 145 

SECTION  XIII.  —  APPLICATION  OF  SUBSTANTIVE  DYES  TO  COTTON. 

82  General  Method  of  Dyeing  Cotton 149 

83  Influence  of  the  Amount  of  Salt  in  the  Dye-bath 150 

84  Use  of  Soda  Ash 150 

85  Use  of  Soap 150 

86  After-treatment  with  Chrome 151 

87  After-treatment  with  Bluestone 151 

88  Dyeing  in  a  Cold  Bath 151 

89  Shading  Substantive  Dyes  with  Basic  Dyes 152 

Notes 153 

Samples  (.247-278) 157 

Quiz  13  (369-415) 157 

SECTION  XIV.  —  SUBSTANTIVE  DYES  ON  WOOL  AND  SILK. 

90  General  Method  of  Dyeing  Wool 161 

91  Use  of  Ammonium  Acetate  in  the  Dye-bath 161 

92  Dyeing  in  a  Slightly  Acid  Bath 162 

93  Showing  the  Application  of  Substantive  Dyes  on  Union  Material 162 


CONTENTS.  IX 

EXP.  PAGE 

94  After-treatment  with  Chrome 163 

95  After-treatment  with  Chromium  Fluoride 163 

96  Example  of  a  Substantive  Dye  not  Coloring  Wool 163 

97  General  Method  of  Applying  Substantive  Dyes  to  Silk 164 

Notes 164 

Samples  (279-297) 167 

Quiz  14  (416-449) 167 


SECTION  XV.  —  REPRESENTATIVE  SUBSTANTIVE  DYES  ON  COTTON. 

98   Representive  Substantive  Dyes 170 

Notes 171 

Samples  (298-327) 181 

Quiz  15  (450-470) 181 


SECTION  XVI.  —  APPLICATION  OF  MORDANT  DYES  TO  WOOL. 

99    General  Method  of  Dyeing    183 

100  Effect  of  Iron  Salts  in  the  Bath 183 

101  Comparison  of  Different  Mordants  on  Wool 184 

102  After- Mordanting  with  Chrome 185 

Notes 186 

Samples  (328-347) 191 

Quiz  16  (471-504) 191 

SECTION  XVII.  —  DEVELOPED  DYES  ON  COTTON  AND  SILK. 

103  General  Method  of  Applying  Developed  Dyes 194 

104  Showing  the  Action  of  Heat  on  the  Diazo  Body 195 

105  Developed  Black  on  Cotton 196 

106  Dyeing  Primuline  on  Silk 196 

107  Dyeing  a  Developed  Black  on  Silk 197 

Notes 197 

Samples  (348-359) 200 

Quiz  17  (505-533) 200 

SECTION  XVIII.  —  SULPHUR  DYES  ON  COTTON. 

108  General  Method  of  Applying  Sulphur  Dyes 203 

109  After-treatment  of  Sulphur  Dyes  with  Chrome 203 

no   Obtaining  Black  with  Sulphur  Dyes 203 

in   Use  of  Autogene  Black 204 

Notes 204 

Samples  (360-373) 208 

Quiz  18  (534-563) 208 


X  CONTENTS. 

SECTION  XIX.  —  USE  OF  LOGWOOD  IN  DYEING. 

EXP.  PAGE 

112  General  Method  of  Dyeing  Logwood  on  Cotton 210 

113  Effect  of  Over-Chroming 210 

114  Shading  Logwood  with  Alizarin  Yellow 210 

115  Logwood  Black  on  Cotton  with  an  Iron  Mordant 211 

116  To  Obtain  a  Faster  and  Clearer  Black 211 

117  Dyeing  Logwood  without  Tannin 212 

118  Dyeing  Silk  a  Pure  Black  with  Logwood 212 

Notes 212 

Samples  (374~386) 215 

Quiz  19  (564-599) 216 


SECTION  XX.  —  THE  MINOR  NATURAL  DYES. 

119  Use  of  Fustic 218 

120  Use  of  Madder 218 

121  Use  of  Archil 219 

122  Use  of  Quercitron 219 

123  Use  of  Cutch 219 

124  Use  of  Cochineal 220 

Notes 220 

Samples  (387-400) 236 

Quiz  20  (600-638) 236 


SECTION  XXI.  —  THE  MINERAL  DYESTUFFS. 

125  Chrome  Yellow  on  Cotton 239 

126  Chrome  Orange  on  Cotton 241 

127  Iron  Buff  on  Cotton 242 

1 28  Iron  Gray  on  Cotton 243 

129  Manganese  Brown  on  Cotton 244 

130  Chrome  Green  on  Cotton 246 

131  Prussian  Blue  on  Cotton  or  Wool 246 

Notes 249 

Samples  (401-419) 252 

Quiz  21  (639-666) 252 


SECTION  XXII. —  THE  VAT  DYES. 

132  Preparation  of  Indigo  Solution 254 

133  Dyeing  Indigo  with  Hydrosulphite  Vat 255 

134  Use  of  Thio-Indigo  Red '.  . .  .  257 

135  Use  of  Indanthrene  Blue 257 

136  Use  of  Indanthrene  Yellow 258 


CONTENTS.  XI 

EXP.  PAGE 

137  Production  of  Fast  Pink  with  Indanthrene  Dyes 258 

138  Use  of  Ciba  Blue 259 

Notes 259 

Samples  (420-435) 263 

Quiz  22  (667-686) 263 


SECTION  XXIII.  —  THE  TESTING  OF  DYESTUFFS. 

139  To  Obtain  the  Money  Value  of  a  Dyestuff  Sample 265 

140  To  Determine  if  a  Dyestuff  is  Simple  or  Mixed 268 

141  To  Determine  the  Class  to  which  a  Dyestuff  Belongs 269 

142  Chemical  Method  of  Distinguishing  between  Acid  and  Basic  Dyestuffs  272 

143  Detection  of  Adulterations  in  Dyestuffs 273 

144  Determination  of  the  Capillary  Speed  of  Dyestuffs 278 

Quiz  23  (687-708) 279 


SECTION  XXIV.  —  CHEMICAL  REACTIONS  OF  DYESTUFFS. 

145  Solubility  Tests 281 

146  Reaction  with  Sulphuric  Acid 281 

147  Reaction  with  Hydrochloric  Acid 282 

148  Reaction  with  Nitric  Acid 282 

149  Reaction  with  Sodium  Hydrate 282 

150  Reaction  with  Ammonia 282 

151  Reaction  with  Sodium  Carbonate 282 

152  Reaction  with  Tannin  Reagent 283 

153  Reaction  with  Alum 283 

154  Reaction  with  Potassium  Bichromate 283 

155  Reaction  with  Ferric  Chloride 283 

156  Reaction  with  Stannous  Chloride 283 

157  Reaction  with  Bleaching  Powder 284 

158  Reaction  with  Zinc  Dust 284 

159  Reaction  with  Zinc  Dust  and  Acetic  Acid 284 

Tabulation  of  Results  with  Chemical  Reagents 285 


SECTION  XXV.  —  MISCELLANEOUS  TESTS  IN  DYEING. 

160  The  Amount  of  Dyestuff  Necessary  for  a  Full  Shade 286 

1 6 1  To  Determine  the  Degree  of  the  Exhaustion  of  the  Dye-bath 286 

162  To  Determine  the  Correct  Amount  of  Mordant  to  Use 287 

163  To  Determine  the  Degree  of  Exhaustion  of  the  Mordant  Bath 288 

164  To  Show  the  Dichroic  Property  of  a  Dyestuff 288 

165  Effect  of  Dichroism  in  the  Compounding  of  Shades 289 

Samples  (436-471) 290 

Quiz  25  (709-716) 291 


xii  CONTENTS. 


SECTION  XXVI.  —  TESTING  THE  FASTNESS  OF  COLORS. 

EXP.                                                              ,  PAGE 

166  Testing  Fastness  of  Colors  Dyed  on  Wool 292 

167  Testing  Fastness  of  Cotton  Dyeings 299 

Tabulation  of  Fastness  Required  on  Various  Classes  of  Materials 301 

Tabulation  of  Tests  for  Fastness  of  Wool  Dyes 302 

Tabulation  of  Tests  for  Fastness  of  Cotton  Dyes 303 

Quiz  26  (717-758) .-. 3°7 


SECTION  XXVII.  —  ANALYSIS  OF  TEXTILE  FABRICS. 

168  To  Determine  the  Amount  of  Wool  and  Cotton  in  a  Fabric 310 

169  Analysis  of  Fabric  Containing  Silk  and  Cotton 310 

170  Analysis  of  Fabric  Containing  Wool  and  Silk 311 

171  Analysis  of  Fabric  Containing  Wool,  Silk,  and  Cotton 311 

172  Distinction  between  True  Silk  and  Artificial  Silk 311 

173  To  Distinguish  between  Cotton  and  Linen 312 

174  To  Distinguish  between  True  Silk  and  Tussah  Silk 313 

Quiz  27  (759-770) 3*3 


SECTION  XXVIII.  —  ANALYSIS  OF  TEXTILE  FABRICS. 

175  Estimation  of  Sizing  and  Dressing  Materials  in  a  Fabric 315 

176  Conditioning  of  Textile  Materials 315 

177  Estimation  of  Oil  and  Grease  in  Fabrics 316 

178  Detection  of  Mineral  Oil  in  Textile  Fabrics 316 

179  Detection  of  Rosin  Oil  in  Textile  Fabrics 317 

180  Estimation  of  Mineral  Matter  in  a  Fabric 317 

181  Determination  of  the  Nature  of  Sizing  on  a  Fabric 317 

182  Determination  of  the  Nature  of  Mordants  on  Woolen  Fabrics 319 

183  Determination  of  the  Nature  of  Mordants  on  Cotton  Fabrics 321 

Quiz  28  (771-791) 323 


APPENDIX. 
USEFUL  DATA  FOR  DYERS  AND  TEXTILE  CHEMISTS. 

1  Hydrometers 325 

2  Equivalents  of  Common  Use  in  Measuring 327 

3  Thermometry 330 

4  Comparison  of  Relative  Strengths  of  Chemicals 330 

5  Tables  Showing  the  Strengths  and  Densities  of  Various  Solutions 331 

6  Tables  for  Calculations  in  Dyeing 336 


Laboratory  Manual  of  Dyeing  and 
Textile  Chemistry 


INTRODUCTORY. 


i.  Apparatus  Required.  —  In  carrying  out  the  dye-tests  herein 
described,  it  will  be  found  convenient  to  employ  skeins  of  wool 
and  silk  weighing  5  grams,  and  of  cotton  10  grams.  The  dye- 
baths  should  contain  about  300  to  400  cc.  of  water,  and  should  be 
of  porcelain,  glass,  or  enameled  iron-ware.  A  good  form  of 
experimental  dye-bath  is  that  shown  in  the  illustration  (Fig.  i). 
It  consists  of  a  round  copper  vessel  lined  inside  with  asbestos,  and 
provided  with  a  perforated  iron  bottom.  Its  top  contains  four 
openings  through  which  the  dye-pots  are  inserted.  This  copper 
air-bath  is  placed  on  an  iron  stand  provided  with  a  gas  burner. 
The  dye-pots  are  of  porcelain  and  are  held  by  beveled  copper  col- 
lars with  wooden  handles.  The  air-bath  is  so  arranged  that  when 
the  dye-pots  are  in  position  they  are  raised  about  an  inch  above 
the  bottom  plate.  Such  a  dye-bath  allows  of  a  uniform  heating 
of  the  four  pots,  and  the  temperature  may  be  raised  rapidly  or 
slowly  at  will,  by  regulation  of  the  gas  flames,  and  it  is  an  easy 
matter  to  bring  the  liquid  in  the  pots  to  an  active  boil.  There 
are  other  forms  of  experimental  dye-baths  in  use  where  solutions 
of  calcium  chloride,  common-salt,  glycerin,  etc.,  are  used  for 
heating  the  dye-pots.  Strong  solutions  of  calcium  chloride  are 
capable  of  being  heated  far  above  the  boiling-point  of  water, 
and  consequently  in  such  a  bath  it  is  easy  to  bring  the  dye-pots 
to  the  boil.  But  calcium  chloride  solutions  attack  the  baths  in 
which  they  are  contained.  In  case  of  copper  vessels  with  soldered 


DYEING  AND    TEXTILE  CHEMISTRY. 


seams  the  solder  is  rapidly  eaten  out  and  leaks  frequently  occur. 
In  a  dye-bath  using  a  solution  of  calcium  chloride  the  seams 
should  be  brazed,  which  makes  the  apparatus  rather  expensive, 
and  even  then  the  copper  itself  is  soon  attacked.  With  solutions 


9   ' 


\,,^£,'4 * 

III 


1  t    it    4 


1 


FIG.  i.  —  Experimental  Dye  Bath. 

of  common-salt  it  is  difficult  to  obtain  a  temperature  of  212°  F. 
in  the  dye-pots;  that  is,  to  bring  them  to  a  state  of  active  boiling. 
A  temperature  of  210°  F.,  however,  can  be  maintained,  and 
probably  this  is  nearer  the  actual  temperature  of  the  open  dye- 
vat  in  practice,  and  gives  as  good  results  as  if  the  liquid  was  in 
an  actual  state  of  ebullition.  Solutions  of  common-salt  are 


INTRODUCTORY.  3 

perhaps  to  be  preferred  to  those  of  calcium  chloride,  as  they  do 
not  have  as  corroding  an  action  on  the  copper  dye-bath.  By  the 
use  of  glycerin  in  the  bath  a  boiling  temperature  can  readily  be 
obtained  in  the  dye-pots,  but  glycerin  baths  continually  emit 
disagreeable  vapors.  Whenever  possible,  baths  containing  such 
solutions  should  be  heated  by  a  steam-coil  (with  steam  under 
pressure)  rather  than  by  direct  gas  flames.  The  great  disad- 
vantage of  all  baths  using  solutions,  and  one  from  which  the 
air-bath  is  free,  is  that  the  water  is  constantly  being  evaporated 
from  the  solution  and  has  to  be  as  constantly  replaced. 

When  dyeing  the  test-skeins  they  should  be  systematically 
"worked"  or  turned  in  the  dye-solution.  This  is  best  accom- 
plished by  suspending  the  skein  in  the  bath  from  two  glass  rods, 
and  using  these  from  time  to  time  for  the  purpose  of  turning  the 
skeins.  These  glass  rods  should  be  one-fourth  to  three-eighths 
inch  in  diameter,  and  8  to  10  inches  in  length.  The  skeins 
should  be  turned  sufficiently  to  insure  even  penetration  of  the 
solution  through  the  entire  portion  of  the  material. 

The  dyestuffs  and  various  chemicals  employed  in  carrying 
out  the  dye-tests  should  be  used  in  the  form  of  solutions  of  such 
strength  that  small  quantities  of  the  products  may  be  measured  out 
in  convenient  volumes.  As  the  amount  of  material  being  dyed 
(5  or  10  grams)  is  relatively  small,  and  as  small  amounts  of  the 
dyestuffs,  etc.,  are  used,  it  would  be  both  inconvenient  and 
inaccurate  (unless  very  precise  weighings  were  made  on  expen- 
sive and  accurate  balances)  to  weigh  the  chemicals  employed  in 
each  test;  but  by  preparing  solutions  of  definite  strengths  the 
required  amounts  may  be  readily  and  accurately  measured  off. 
The  proper  preparation  of  these  solutions  will  be  taken  up  as 
demanded  by  the  course  of  the  experiments.  For  the  measure- 
ment of  the  solutions  a  glass  cylinder  graduated  into  100  cc.  is 
very  convenient;  this  readily  permits  of  the  rather  accurate 
measurement  of  such  quantities  as  5  cc.,  10  cc.,  etc.  In  cases 
where  very  minute  quantities  are  desired,  and  it  is  necessary 
to  measure  to  an  accuracy  of  y1^  cc.,  a  small  glass  tube  (known 
as  Mohr's  pipette)  accurately  graduated  to  ^  cc.  is  very  useful. 


4  DYEING   AND    TEXTILE   CHEMISTRY. 

These  pipettes  may  be  obtained  in  sizes  holding  5,  10,  25, 
or  50  cc.,  and  by  their  use  volumes  accurate  to  -^  cc.  may  be 
readily  measured  out.  A  thermometer  is  also  necessary  for 
use  in  the  dye-tests.  A  good,  practical,  and  inexpensive  form 
is  the  so-called  "  dairy  "  thermometer  with  a  paper  scale  and 
reading  to  220°  F.  By  the  use  of  this  thermometer  the  tem- 
peratures of  the  dye-solutions  or  other  liquids  employed  in 
the  tests  may  be  ascertained.  An  agate  cup  (pint  or  quart  size) 
is  a  useful  adjunct  for  the  preparation  and  mixing  of  the  various 
solutions  needed.  A  bunch  of  small  tags  should  also  be  avail- 
able so  that  every  skein  with  which  a  test  has  been  made  may 
be  properly  labelled  for  identification  and  reference.* 

*  The  following  is  a  list  of  apparatus  supplied  as  an  equipment  to  each  indi- 
vidual student  in  the  dye  laboratory  of  the  Philadelphia  Textile  School: 

One  dye-bath  (for  four  pots). 

Four  porcelain  beakers  (320  cc.). 

Four  copper  collars  (with  wooden  handles). 

Twelve  glass  rods  (£  inch  diameter  by  8  inches  in  length). 

One  dairy  thermometer  (to  220°  F). 

One  graduated  cylinder  (100  cc.). 

One  Mohr's  pipette  (10  cc.  divided  into  tenths). 

One  agate  cup  (pint). 

One  bunch  tags  (with  white  strings). 


SECTION  I. 
CHEMICAL  STUDY  OF  THE  FIBRES. 

Experiment  i.  Action  of  Acids  on  Wool  and  Cotton.  —  Place 
about  300  cc.  of  water  in  one  of  the  porcelain  beakers  employed 
for  the  dye-tests,  and  add  2  cc.  of  concentrated  sulphuric  acid. 
In  this  "bath"  boil  a  test-skein  of  woolen  yarn  together  with 
one  of  cotton  yarn  for  20  minutes;  then  remove  the  skeins, 
squeeze  out  the  excess  of  liquid,  and  dry  without  washing. 
After  drying  test  the  strength  of  the  two  skeins,  and  it  will  be 
found  that  the  cotton  (i)*  has  been  very  much  weakened  and 
may  be  easily  pulled  apart,  whereas  the  wool  (2)  does  not  appear 
to  have  been  much  affected.  Boil  a  second  set  of  woolen  and 
cotton  skeins  in  the  same  acid  bath  for  20  minutes,  then  wash 
well  in  several  changes  of  fresh  water.  Take  the  woolen  skein 
and,  together  with  another  one  of  untreated  wool,  dye  by  boiling 
for  20  minutes  in  a  beaker  containing  300  cc.  of  water  and  10  cc. 
of  Acid  Magenta  solution  (containing  5  grams  of  the  dissolved 
dyestuff  per  liter) ;  then  wash  well  and  dry.  It  will  be  noticed 
that  the  skein  which  has  been  treated  with  acid  (3)  will  be  dyed 
a  heavier  color  than  the  second  skein  (4).  This  is  due  to  the 
wool  having  combined  chemically  with  the  acid  in  its  first  treat- 
ment, thus  allowing  it  to  react  more  readily  with  the  acid  dyestuff 
employed.  Take  the  second  cotton  skein  and  pass  it  through  a 
cold  solution  of  i  gram  of  soda  ash  in  300  cc.  of  water  for 
10  minutes;  then  rinse  in  fresh  water  and  dry.  It  will  be  found 
that  this  skein  (5)  has  not  become  weakened  by  the  treatment 

*  The  parenthetical  numbers  refer  to  samples  to  be  taken  from  the  tests  by  the 
student,  and  correspond  to  the  sample  numbers  given  in  a  list  at  the  end  of  each 
section.  These  samples  should  be  neatly  and  systematically  mounted  in  a  book 
specially  prepared  to  receive  them,  and  each  one  should  be  properly  numbered 
and  labelled,  and  should  have  the  careful  criticism  of  the  instructor. 


6  DYEING   AND    TEXTILE   CHEMISTRY. 

with  the  acid  solution,  as  the  latter  has  been  neutralized  by  the 
alkali  before  drying. 

Experiment  2.  Action  of  Organic  Acids  on  Cotton.  —  Work  a 
test-skein  of  cotton  yarn  in  a  bath  containing  300  cc.  of  water 
and  5  cc.  of  acetic  acid  for  20  minutes  at  a  temperature  of  160°  F. 
Squeeze  and  dry  without  washing.  Test  the  strength  of  the  dried 
skein  (6)  and  it  will  be  found  not  to  have  become  much  weakened. 
Acetic  acid  is  a  volatile  organic  acid  and  on  drying  is  volatilized 
from  the  fibre. 

Experiment  3.  Action  of  Alkalies.  —  Boil  a  skein  of  woolen 
yarn  together  with  one  of  cotton  in  a  bath  containing  300  cc.  of 
water  and  10  cc.  of  caustic  soda  solution  (60°  Tw.).  The  wool  will 
be  disintegrated  and  dissolved  (7) .  Wash  and  dry  the  cotton  skein 
and  it  will  be  found  not  to  be  appreciably  altered  (8).  Repeat 
the  test,  using  10  cc.  of  a  solution  of  sodium  carbonate  instead  of 
caustic  soda.  Boil  for  20  minutes,  then  wash  and  dry.  It  will 
be  found  that  the  wool  has  become  much  weakened  and  is  life- 
less and  dull  in  appearance  (9),  while  the  cotton  is  not  changed 
(10).  Repeat  this  test,  using  10  cc.  of  a  solution  of  ammonium 
carbonate;  boil  for  20  minutes,  then  wash  and  dry.  It  will  be 
noticed  that  in  this  case  neither  the  wool  (n)  nor  the  cotton  (12) 
is  affected  in  strength. 

Experiment  4.  Action  of  Metallic  Salts  (Mordants) .  —  Boil  a 
skein  of  wool  together  with  one  of  cotton  for  20  minutes  in  a  bath 
cc  ntaining  300  cc.  of  water,  and  10  cc.  of  chrome  solution.  Rinse 
with  fresh  water.  Then  boil  the  woolen  skein  together  with 
another  of  untreated  wool  in  a  bath  containing  300  cc.  of  water 
and  20  cc.  of  a  solution  of  madder.  Finally  wash  well  and  dry. 
It  will  be  found  that  the  untreated  skein  (13)  has  not  become 
dyed,  whereas  that  treated  with  the  chrome  has  become  colored 
(14).  Take  the  cotton  skein  which  has  been  treated  with  the 
chrome  and  boil  it  also  in  a  solution  containing  300  cc.  of  water 
and  20  cc.  of  madder  solution,  then  wash  well  and  dry  (15).  It 
will  be  found  that  the  cotton  skein  has  taken  up  but  very  little 
dyestuff ,  as  this  fibre  absorbs  but  a  small  amount  of  the  mordant. 
Madder  is  a*  dye  which  has  no  direct  affinity  for  the  fibres,  but  it 


CHEMICAL   STUDY   OF   THE  FIBRES.  / 

forms  a  color-lake  with  metallic  salts  such  as  chrome;  hence  the 
unmordanted  wool  did  not  become  dyed.  Due  to  the  fact  that 
wool  has  a  much  greater  affinity  for  metallic  salts  than  cotton, 
it  will  be  noticed  that  the  former  fibre  is  dyed  much  deeper  than 
the  latter. 

Experiment  5.  Action  of  Bleaching  Powder.  —  Steep  a  skein 
of  woolen  yarn  together  with  one  of  cotton  in  a  cold  solution  of 
bleaching  powder  of  about  2°  Tw.  strength  for  30  minutes.  Then 
pass  into  a  cold  bath  containing  300  cc.  of  water  and  10  cc.  of  a 
dilute  solution  of  hydrochloric  acid  (the  odor  of  what  gas  is  noticed 
here)  and  work  for  10  minutes.  Then  wash  well  in  fresh  water. 
It  will  be  found  that  the  cotton  (16)  has  become  bleached,  but 
that  the  wool  (17)  has  acquired  a  deeper  yellow  tint  and  is  harsh 
in  feel  after  drying.  The  wool  has  combined  with  the  chlorine 
of  the  bleaching  powder  in  a  chemical  manner  while  the  cotton 
has  not;  the  only  effect  in  the  latter  case  being  that  the  bleaching 
liquor  destroys  the  coloring-matter  naturally  present  in  the  cotton. 
Next,  take  this  skein  of  " chlorinated"  wool  together  with  a  skein 
of  untreated  wool  and  dye  them  for  20  minutes  at  160°  F.  in  a  bath 
containing  300  cc.  of  water  and  5  cc.  of  a  solution  of  Diamine  Sky 
Blue;  wash  and  dry.  It  will  be  found  that  the  "chlorinated  "  skein 
(18)  takes  up  much  more  dyestuff  than  the  other  skein  (19)  and 
is  dyed  a  darker  shade.  Next,  take  portions  of  these  two  skeins 
and  plait  them  together  and  steep  in  a  small  quantity  of  warm 
soap  solution  and  rub  vigorously  between  the  hands  to  imitate 
the  action  of  fulling  or  milling.  It  will  be  found  that  the  ordinary 
wool  (20)  will  readily  felt  together,  while  the  chlorinated  wool  (21) 

does  not. 

NOTES. 

i.  Action  of  Acids  on  Wool  and  Cotton.  —  The  animal  and 
vegetable  fibres  show  a  marked  contrast  in  their  behavior  with 
acids.  Wool  absorbs  mineral  acids  (sulphuric,  hydrochloric,  and 
nitric)  from  solution  and,  unless  the  acid  is  quite  concentrated, 
the  fibre  is  not  decomposed.  The  acid,  in  this  case,  no  doubt 
combines  chemically  with  the  wool  on  account  of  the  basic  nature 
of  this  fibre.  This  is  evidenced  by  the  fact  that  wool  which  has 


8  DYEING  AND    TEXTILE  CHEMISTRY. 

been  treated  with  acid  will  dye  with  acid  coloring-matters  much 
better  than  ordinary  wool.  Also,  when  wool  is  treated  with  a 
solution  containing  sulphuric  acid  and  then  washed  until  the 
wash  waters  are  neutral,  there  will  still  be  some  of  the  acid 
remaining  in  the  wool.  Cotton,  on  the  other  hand,  is  rather 
easily  affected  by  solutions  of  the  mineral  acids,  especially  when 
such  a  solution  is  allowed  to  dry  into  the  fibre.  Cotton  does  not 
possess  any  basic  qualities,  and  therefore  does  not  combine  chemi- 
cally with  the  acid,  thereby  neutralizing  it,  as  in  the  case  of  wool. 
Unless  employed  in  very  weak  solutions,  all  the  mineral  acids 
have  a  tendering  action  on  cotton,  causing  a  disintegration  of  the 
fibre  through  a  breaking  down  of  the  cellulose  molecule  of  which 
the  cotton  is  composed.  The  compound  of  cellulose  so  formed  is 
known  as  hydrated  cellulose  and  is  brittle  in  nature.  On  this 
difference  in  the  reaction  of  wool  and  cotton  with  acids  is  based 
the  process  of  ''carbonizing"  or  separating  vegetable  fibres  from 
wool  in  woven  fabrics  or  in  shoddy  where  it  is  desired  to  recover 
the  wool  and  eliminate  the  cotton.  Organic  acids  (such  as 
formic,  acetic,  oxalic,  and  tartaric)  do  not  have  the  same  ten- 
dering action  on  cotton  as  the  mineral  acids;  formic  and  acetic 
acids,  being  both  volatile,  are  removed  from  the  fibre  on  drying 
and  hence  do  not  injure  cotton;  oxalic  and  tartaric  acids,  on  the 
other  hand,  are  not  volatile,  and  if  strong  solutions  are  used 
somewhat  tender  the  cotton  when  drying. 

2.  Action  of  Alkalies  on  Wool  and  Cotton.  —  Alkalies  react 
with  the  animal  and  vegetable  fibres  in  just  the  opposite  manner 
to  acids.  Caustic  soda,  even  in  very  dilute  solutions  and  at  not 
very  high  temperatures,  will  completely  disintegrate  and  dissolve 
the  wool  fibre;  whereas  cotton  is  not  affected.  Even  with  solu- 
tions of  sodium  carbonate  (soda  ash)  the  wool  fibre  will  be 
seriously  weakened  and  injured  in  appearance  unless  such  solu- 
tions are  comparatively  weak  and  employed  at  rather  low  tem- 
peratures. Due  to  these  facts  caustic  soda  cannot  be  used  for 
the  scouring  of  wool,  nor  should  it  be  used  in  any  connection  with 
wool.  Soda  ash  when  employed  in  scouring  or  any  other  process 
in  contact  with  wool,  must  be  carefully  handled  in  order  that  the 


CHEMICAL  STUDY   OF   THE  FIBRES.  9 

solution  of  the  same  does  not  become  too  concentrated  nor 
heated  too  high.  Cotton,  on  the  other  hand,  is  scoured  by  the 
use  of  boiling  caustic  soda  or  soda  ash  without  fear  of  being 
injured.  Ammonium  carbonate  and  ammonia  water  are  much 
milder  in  their  alkaline  action  and  do  not  have  any  injurious  effect 
on  wool  at  ordinary  concentrations,  on  which  account  they  make 
very  good  scouring  compounds,  although  too  expensive  for  the 
majority  of  materials. 

3.  Action  of  Metallic  Salts  on  Wool  and  Cotton.  —  Wool  is 
quite  reactive  towards  solutions  of  the  majority  of  metallic  salts, 
absorbing  the  most  of  them  from  solution  and  fixing  the  oxide 
of  the  metal  in  chemical  combination  with  the  fibre.  For 
instance,  when  wool  is  boiled  with  a  dilute  solution  of  potassium 
bichromate  (chrome),  the  latter  salt  becomes  decomposed  to  a  con- 
siderable extent  and  quite  a  proportion  of  chromium  oxide  becomes 
chemically  combined  with  the  fibre.  This  fact  is  evidenced  by 
the  wool  showing  the  presence  of  the  metallic  compound  by  its 
color  and  by  being  able  to  form  a  color-lake  with  certain  dye- 
stuffs  which  will  not  combine  directly  with  ordinary  wool.  Cotton, 
on  the  other  hand,  has  but  very  slight  affinity  for  metallic  salts, 
being  very  inert  in  this  connection,  as  the  fibre  does  not  appear 
to  be  able  to  absorb  and  fix  the  metallic  oxide  as  in  the  case  of 
wool.  This  action  of  wool  with  metallic  salts  forms  the  basis 
of  the  operations  of  mordanting  wool  preliminary  to  the  dyeing 
with  the  alizarin  and  other  mordant  colors  which  require  a  base 
of  some  metallic  oxide  with  which  to  form  a  color-lake;  and 
also  due  to  the  inert  character  of  cotton,  this  fibre  cannot  be 
readily  dyed  with  these  colors.  Bleaching  powder  has  a  peculiar 
action  on  wool;  this  chemical  is  a  strong  oxidizing  agent  and 
in  hot  solutions  of  any  considerable  concentration  will  rapidly 
disintegrate  the  wool  fibre.  In  cold  and  dilute  solutions, 
however,  a  chemical  combination  apparently  takes  place  between 
the  wool  and  the  chlorine  evolved  by  the  bleaching  powder, 
giving  a  product  known  as  "chlored"  or  "  chlorinated "  wool 
without  much  physical  alteration  of  the  fibre.  Wool  so  treated 
exhibits  a  much  stronger  affinity  towards  many  coloring-matters, 


10  DYEING   AND    TEXTILE   CHEMISTRY. 

and  almost  completely  loses  its  felting  properties,  and  acquires 
a  higher  luster.  Cotton  does  not  combine  with  the  chlorine  of 
the  bleaching  powder,  but  shows  the  strong  oxidizing  action  of 
the  latter  in  becoming  bleached.  This  reaction  is  the  basis 
of  the  method  of  bleaching  cotton  materials. 

SAMPLES. 

1.  Cotton  treated  with  mineral  acid;  showing  weakness. 

2.  Wool  treated  with  acid;  not  weakened. 

3.  Wool  treated  with  acid  and  dyed. 

4.  Wool  not  treated  with  acid  and  dyed. 

5.  Cotton  treated  with  mineral  acid,  then  neutralized  with  an  alkali;  not 
weakened. 

6.  Cotton  treated  with  organic  acid;  not  weakened. 

7.  Wool  boiled  with  caustic  soda;  dissolved. 

8.  Cotton  boiled  with  caustic  soda;  not  affected. 

9.  Wool  boiled  with  solution  of  soda  ash;  much  injured. 

10.  Cotton  boiled  with  solution  of  soda  ash;  not  affected. 

11.  Wool  boiled  with  solution  of  ammonium  carbonate;  not  injured. 

12.  Cotton  boiled  with  solution  of  ammonium  carbonate;  not  affected. 

13.  Unmordanted  wool  dyed  with  madder. 

14.  Wool  treated  with  chrome  and  dyed  with  madder. 

15.  Cotton  treated  with  chrome  and  dyed  with  madder. 

1 6.  Cotton  treated  with  bleaching  powder;  becomes  bleached. 

17.  Wool  treated  with  bleaching  powder;  becomes  yellowish. 

18.  Chlorinated  wool  dyed. 

19.  Unchlorinated  wool  dyed  for  comparison. 

20.  Unchlorinated  wool  fulled  with  soap. 

2 1 .  Chlorinated  wool  fulled  with  soap. 

QUIZ  I. 

1 .  What  is  the  effect  of  allowing  acid  solutions  to  dry  in  the  cotton  fibre  ? 
How  does  wool  differ  in  this  respect  ? 

2 .  After  treatment  with  solutions  containing  non-volatile  acids,  why  should 
cotton  be  very  .thoroughly  washed  before  drying? 

3.  What  is  the  difference  in  the  chemical  nature  of  organic  and  mineral 
acids  ?     Name  several  representatives  in  each  class. 

4.  Why  do  solutions  of  acetic  acid  not  have  the  same  weakening  action  on 
cotton  as  solutions  of  sulphuric  acid?     Does  oxalic  acid  behave  any  dif- 
ferently from  acetic  acid  and  why  ? 

5.  Why  is  it  preferable  to  use  acetic  acid  in  connection  with  cotton  rather 
than  sulphuric  acid  ? 


CHEMICAL  STUDY   OF   THE  FIBRES.  II 

6.  Does  wool  combine  in  a  chemical  manner  with  sulphuric  acid?    How 
can  this  be  shown  ? 

7.  If  it  is  necessary  to  treat  cotton  with  acid  solutions,  how  may  the  inju- 
rious effects  of  the  acid  be  prevented  ? 

8.  What  is  the  action  of  dilute  solutions  of  caustic  soda  on  wool?     On 
cotton  ? 

9.  Can  wool  be  boiled  with  soda  ash  solutions  without  injury? 

10.  Do  boiling  solutions  of  soda  ash  have  any  injurious  action  on  cotton? 

1 1 .  How  do  solutions  of  ammonium  carbonate  react  with  wool  and  cotton  ? 

1 2 .  Why  should  soaps  used  in  scouring  wool  be  free  from  caustic  alkali  ? 

13.  Solutions  of  soda  ash  are  largely  used  for  scouring  wool;  why  should 
not  such  scouring  baths  be  used  at  a  boiling  temperature? 

14.  What  is  meant  by  a  mordant? 

15.  What  is  the  action  of  solutions  of  potassium  bichromate  on  wool? 
Explain  the  chemical  reaction  which  takes  place. 

1 6.  Metallic  salts  of  what  character  are  useful  as  mordants  for  wool? 
What  is  meant  by  the  "dissociation"  of  a  salt? 

17.  How  does  mordanted  wool  react  with  a  solution  of  madder? 

1 8.  How  does  cotton  differ  from  wool  in  its  action  towards  solutions  of 
metallic  salts? 

19.  Why  are  coloring-matters  employed  with  a  metallic  mordant    more 
useful  on  wool  than  on  cotton  ? 

20.  What  is  bleaching  powder?    Which  of  its  components  is  the  active 
bleaching  agent  ? 

21.  What  is  meant  by  a  degree  Twaddle?     Explain  how  densities  are 
determined  with  a  Twaddle  hydrometer. 

22.  The  odor  of  what  gas  is  noticed  when  the  solution  of  bleaching  powder 
is  brought  in  contact  with  hydrochloric  acid?     Give  the  chemical  reaction 
taking  place. 

23.  Describe  the  effect  of  bleaching  powder  solutions  on  wool.     Why  can- 
not this  substance  be  employed  for  bleaching  wool  ? 

24.  What  is  the  action  of  bleaching  powder  on  cotton? 

25.  What  is  meant  by  "chlorinated"  wool?    How  does  such  wool  differ 
from  ordinary  wool  in  its  behavior  with  dyestuffs  ? 

26.  What  effect  has  the  chlorination  of  wool  on  its  felting  properties? 


SECTION   II. 
SCOURING  THE  TEXTILE  FIBRES. 

Experiment  6.   Scouring  Raw  Wool  by  the  Emulsion  Process.  — 

Weigh  out  10  grams  of  raw  wool  (22)  and  scour  it  in  a  bath 
containing  300  cc.  of  water,  5  grams  of  soda  ash,  and  2  grams 
of  soap.  Have  the  soap  thoroughly  dissolved  before  adding 
it  to  the  bath.  Work  the  wool  gently  at  140°  F.  for  one-half 
hour,  or  until  it  seems  thoroughly  cleansed.  Wash  well  in  fresh 
warm  water  to  remove  all  soapy  liquor.  Dry  (23)  and  reweigh. 
Calculate  the  percentage  of  loss  or  "  shrinkage."  In  working 
the  wool  in  the  scouring  bath  care  should  be  taken  not  to  agitate 
the  fibres  too  vigorously  or  the  wool  will  become  matted  or  felted 
together. 

Experiment  7.  Use  of  Potash  in  Scouring  Wool.  —  Prepare 
a  scouring  bath  containing  300  cc.  of  water,  5  grams  of  pearl  ash 
(potassium  carbonate  or  potash),  and  2  grams  of  soap.  Scour 
a  lo-gram  sample  of  the  same  wool  as  used  above  and  proceed 
in  the  same  manner.  Wash  well  in  warm  water,  allow  to  dry  (24) 
and  reweigh.  Compare  the  two  samples  thus  scoured  by  the 
use  of  the  two  alkalies. 

Experiment  8.  Effect  of  High  Temperatures  in  Scouring.  - 
Use  the  same  bath  as  employed  in  Exp.  6  and  scour  another 
lo-gram  sample  of  the  same  Kind  of  raw  wool,  but  bring  the 
bath  to  the  boil  for  one-half  hour.  Rinse  as  before  in 
warm  water,  and  allow  to  dry  (25).  Reweigh  and  calculate 
the  percentage  of  loss,  and  also  compare  the  general  appear- 
ance and  "  feel  "  of  the  wool  with  that  scoured  in  the  first 
experiment. 

Experiment  9.  Effect  of  Using  Excessive  Alkali  in  Scouring  Raw 
Wool.  —  Scour  a  lo-gram  sample  of  raw  wool  in  a  bath  contain- 
ing 300  cc.  of  water  and  20  grams  of  soda  ash.  Work  for  one- 


SCOURING    THE   TEXTILE  FIBRES  13 

half  hour  at  a  temperature  of  140°  F.;  then  wash  well  in  warm 
water  and  allow  to  dry  (26).  Calculate  the  percentage  of  loss, 
and  compare  the  general  appearance  and  feel  with  the  samples 
scoured  by  the  use  of  less  alkali. 

Experiment  10.  Scouring  Woolen  Yarn  by  the  Usual  Method.  - 
Prepare  a  bath  containing  300  cc.  of  water,  10  grams  of  soap, 
and  2  grams  of  soda  ash.  Scour  a  weighed  test-skein  of 
woolen  yarn  (27)  in  this  bath  for  one-half  hour  at  a  tempera- 
ture of  140°  F.,  then  wash  in  fresh  water  and  allow  to  dry  (28). 
Reweigh  after  drying  and  calculate  the  percentage  of  loss  due 
to  scouring. 

Experiment  n.  Scouring  Woolen  Yarn  Containing  Iron. — 
Yarn  of  this  nature  is  best  scoured  in  baths  containing  only  soap, 
as  soda  ash  or  potash  will  form  an  insoluble  compound  with  the 
iron  in  the  fibre  which  cannot  be  removed,  and  which  will  cause 
the  yarn  to  dye  up  dull.  Scour  a  test-skein  of  woolen  yarn 
containing  iron  (29)  in  the  same  bath  as  employed  for  the  previous 
experiment  and  in  the  same  manner;  wash  well  and  dry  (30). 
Scour  a  second  skein  of  similar  yarn  in  a  bath  containing  300  cc. 
of  water  and  10  grams  of  soap  for  one-half  hour  at  140°  F.; 
wash  well  and  dry  (31).  Compare  the  appearance  of  the  two 
scoured  skeins. 

Experiment  12.  Scouring  Cotton  with  Caustic  Soda.  —  Prepare 
a  bath  containing  5  grams  of  caustic  soda  to  300  cc.  of  water, 
and  boil  a  skein  of  cotton  yarn  (32)  therein  for  one-half  hour; 
then  wash  in  fresh  water  until  all  trace  of  the  caustic  soda  has 
been  removed  from  the  cotton  and  dry  (33).  Weigh  the  skein 
before  and  after  the  scouring  and  calculate  the  percentage  of 
loss. 

Experiment  13.  Scouring  Cotton  with  Soda  Ash.  —  Prepare  a 
bath  containing  5  grams  of  soda  ash  and  300  cc.  of  water,  and 
boil  a  skein  of  cotton  yarn  therein  for  i  hour.  Wash  well  in 
fresh  water  and  dry  (34).  Weigh  the  skein  before  and  after 
scouring  and  calculate  the  percentage  of  loss.  Compare  this 
skein  with  that  in  the  preceding  test  as  to  amount  of  loss,  color, 
softness,  etc. 


14  DYEING   AND    TEXTILE   CHEMISTRY. 

Experiment  14.  Scouring  Cotton  with  Soap.  —  Prepare  a  bath 
containing  5  grams  of  soap  and '300  cc.  of  water,  and  boil  a 
weighed  skein  of  cotton  yarn  therein  for  one-half  hour.  Wash  in 
fresh  water  and  dry  (35).  Reweigh  and  calculate  the  percent- 
age of  loss.  Compare  this  skein  with  the  others  of  the  above 
experiments. 

Experiment  15.  Scouring  Cotton  with  Fankhausine.  —  Prepare 
a  bath  containing  2  cc.  of  Fankhausine  (50  per  cent  solution)  and 
300  c.c.  of  water.  Work  a  skein  of  cotton  yarn  in  this  bath 
for  one-half  hour  at  i8o°F.;  then  wash  and  dry  (36).  Weigh 
the  skein  before  and  after  scouring  and  calculate  the  percentage 
of  loss.  Compare  the  skein  with  others  in  the  previous  experi- 
ments as  to  color,  softness  of  feel,  etc. 

Experiment  16.  Scouring  of  Raw  Silk.  —  The  fibre  proper  of 
raw  silk  is  covered  with  a  glue-like  material  known  as  sericin. 
The  presence  of  this  latter  substance  makes  raw  silk  harsh  and 
stiff  and  without  lustre.  Boiling  soap  solutions  remove  the  sericin 
without  affecting  the  fibre  proper  of  the  silk.  The  scouring 
of.  silk  is  known  as  "boiling-off,"  "stripping,"  or  "degum- 
ming."  The  silk  will  lose  about  25  per  cent,  in  weight  if  com- 
pletely boiled  off.  Take  a  weighed  skein  of  raw  silk  yarn  (37) 
and  boil  it  for  one  hour  in  a  solution  containing  250  cc.  of  water 
and  25  grams  of  olive  oil  hard  soap;  then  wash  well  in  fresh 
warm  water  and  dry  (38).  Reweigh  and  calculate  the  per- 
centage of  loss.  As  a  rule,  to  completely  degum  the  silk  it  is 
necessary  to  boil  in  several  soap  baths.  Notice  the  difference  in 
the  appearance  and  "  handle  "  of  the  boiled-off  silk.  Stretch  and 
squeeze  the  dried  boiled-off  skein  so  as  to  soften  up  the  fibre 
and  lustre  it  (39).  It  will  be  found  that  most  of  the  coloring- 
matter  of  the  raw  silk  is  in  the  sericin  and  is  removed  in  the 
boiling-off.  The  soap  liquor  left  after  boiling-off  the  silk  is 
known  as  "boiled-off  liquor,"  and  is  used  extensively  as  an  addi- 
tion to  the  dye-bath  in  the  general  dyeing  of  silk.  The  soap 
employed  for  scouring  silk  should  be  of  the  best  quality  and  as 
neutral  as  possible. 


SCOURING   THE   TEXTILE  FIBRES.  15 

NOTES. 

i.  Impurities  in  Raw  Wool.  —  The  raw  wool  fibre  as  it  exists 
in  the  fleece  contains  a  large  amount  of  natural  impurities. 
These  are  as  follows: 

a.  Grease,  or  wool  fat. 

b.  Suint,  or  dried-up  perspiration. 

c.  Dirt,  consisting  of  dust,  sand,  burrs,  etc. 

It  is  the  object  of  scouring  to  remove  these  impurities  and  leave 
the  fibre  pure  and  clean  without  material  injury  to  its  good 
qualities.  The  greasy  matters  in  the  fleece,  known  as  wool-fat, 
are  insoluble  in  water  but  are  readily  emulsified  by  solutions  of 
soaps  or  alkalies.  Wool-fat  differs  from  most  other  animal  fats 
in  chemical  constitution  in  that  the  latter  are  compounds  of 
various  fatty  acids  with  glycerin  (and  hence  are  called  glycerides). 
These  rather  easily  react  with  caustic  alkalies  to  form  soluble 
soaps,  a  reaction  which  is  termed  saponification.  Wool-fat, 
however,  is  not  a  glyceride,  but  contains  a  substance  known  as 
cholesterol  (a  body  belonging  to  the  general  class  of  alcohols), 
and  does  not  form  soaps  with  the  caustic  alkalies.  It  does, 
however,  form  emulsions  with  more  ease  than  do  the  other 
animal  fats,  and  on  this  account  it  is  rather  easily  removed  from 
the  fibre.  The  suint  (a  French  word  for  sweat)  consists  of 
various  metallic  salts  of  organic  acids,  such,  for  instance,  as 
potassium  acetate.  These  salts  are  soluble  in  water  and  hence 
are  easily  removed  in  the  scouring.  The  miscellaneous  dirt  in 
the  wool  is  not  soluble  in  water  and  is  simply  mechanically 
removed  by  the  agitation  of  the  wool  in  the  process  of  scouring. 
The  amount  of  impurities  in  raw  wool  varies  quite  largely  with 
the  character  of  the  sheep  and  the  locality  in  which  they  are 
grown.  Generally  speaking,  the  total  impurities  may  be  said  to 
vary  from  50  to  80  per  cent,  of  the  weight  of  the  fleece,  with  a 
general  average  of  about  65  per  cent.  As  a  rule,  the  finer  the 
staple  of  the  wool,  the  greater  amount  of  grease  it  will  contain; 
whereas  in  coarse  wools  the  amount  of  grease  is  usually  relatively 


16  DYEING  AND    TEXTILE  CHEMISTRY. 

much  less.  The  loss  in  weight  that  wool  undergoes  on  scouring 
is  termed  its  shrinkage,  and  forms  an  important  item  in  judging 
the  value  of  raw  wools. 

The  chemicals  chiefly  employed  in  the  usual  method  of  scour- 
ing wool  are  soda  ash  (sodium  carbonate)  and  soaps.  Potash 
(potassium  carbonate)  is  sometimes  used,  but  as  it  is  much  more 
expensive  than  soda  ash  its  use  is  more  restricted.  Most  fre- 
quently a  mixture  of  soda  ash  and  soap  is  used,  the  relative 
amounts  depending  on  the  quality  of  the  wool  to  be  scoured  and 
the  amount  and  nature  of  the  impurities  present.  As  the  wool 
fibre  is  rapidly  injured  by  solutions  of  alkalies  at  high  tempera- 
tures, the  scouring  of  wool  should  be  carried  out  at  as  low  a 
temperature  as  permissible  with  perfect  removal  of  the  impuri- 
ties. The  temperature  of  the  scouring  bath  under  ordinary 
conditions  should  not  exceed  140°  F.,  and  in  the  case  of  fine 
lustre-wools  the  lower  temperature  of  100°  to  i2o°F.  is  used. 
Attention  has  already  been  drawn  to  the  fact  that  wool  is  easily 
injured  by  even  quite  dilute  solutions'*  of  caustic  alkalies,  con- 
sequently the  presence  of  such  is  especially  deleterious.  On 
this  account,  the  soaps  and  other  ingredients  used  in  the  scouring 
solutions  should  be  free  from  any  very  appreciable  amount  of 
caustic  alkali.  After  removal  from  the  soap  solution,  the  scoured 
wool  should  be  thoroughly  cleansed  from  alkali  and  soap  by 
washing  in  water.  If  this  is  not  done  the  soap  will  dry  into  the 
fibre,  and  subsequently  be  very  difficult  to  properly  remove. 
The  presence  of  soapy  matters  in  the  wool  leads  to  many  bad 
effects;  it  causes  the  product  to  have  a  sticky  and  greasy  feel, 
produces  unevenness  in  dyeing,  and  when  brought  into  an  acid 
solution  (as  is  generally  the  case  in  the  application  of  most  dye- 
stuffs  to  wool) ,  the  soap  is  decomposed  with  the  liberation  of  free 
fatty  matter  in  the  fibre,  which  is  a 'very  objectionable  result. 

2.  The  Emulsion  Process  of  Scouring.  —  The  ordinary  process 
of  scouring  wool  by  the  use  of  solutions  of  soaps  and  alkalies  is 
called  an  " emulsion"  process  on  account  of  the  fact  that  the 
soapy  and  alkaline  liquors  form  an  emulsion  with  the  greasy 
matters  in  the  wool.  A  distinction  must  be  made  between  an 


SCOURING   THE   TEXTILE  FIBRES.  I/ 

emulsion  and  a  solution.  An  emulsion  is  an  intimate  mixture  of 
greasy  or  oily  matters  with  water  (or  solution  of  soap  or  alkali)  in 
which  the  grease  exists  disseminated  throughout  the  mixture  in  a 
very  finely  divided  state ;  usually  in  the  form  of  minute  globules. 
The  emulsion  is  considered  as  permanent  when  the  greasy 
matters  do  not  readily  separate  from  the  liquid  in  a  distinct 
layer.  In  a  solution,  on  the  other  hand,  the  dissolved  substance 
is  not  merely  broken  up  into  small  particles  and  held  in  suspen- 
sion, but  its  identity  becomes  merged  with  that  of  the  liquid 
solvent.  It  is  to  be  noted  that  the  greasy  matters  of  the  wool  do 
not  actually  pass  into  solution  but  remain  finely  suspended  as  an 
emulsion,  and  in  consequence  of  this  may  be  separated  from  the 
scouring  liquor  by  suitable  mechanical  treatment.  The  suint, 
on  the  other  hand,  passes  into  solution. 

3.  Use  of  Alkali  in  Scouring.  —  In  adjusting  the  amount  of 
alkali  (soda   ash)    to  be   used   in   scouring,  reference  must  be 
had  to  the  quality  and  quantity  of  impurity  in  the  wool,  and 
also  to  the  quality  of  the  fibre.      An  excessive  amount  of  alkali 
must  be  guarded  against,  as  it  is  liable  to  injure  the  lustre  and 
strength  of  the  fibre,  and  also  tends  to  discolor  it.     The  finer  the 
quality,  of  the  fibre,  as  a  rule,  the  less  the  amount  of  alkali  that 
should  be  employed,  and  this  is  especially  true  of  lustre- wools 
and  fine  merinos.     Coarser  and  lower  grade  wools  are  scoured 
with  a  relatively  larger  amount  of  alkali.     It  is  a  mistake  to  pre- 
sume that  the  more  dirty  and  greasy  the  wool,  the  more  alkaline 
should  be  the  scouring  liquors;  this  may  be  true  when  reference 
is  had  to  wools  of  about  the  same  quality,  but  a  very  dirty  and 
greasy  fine  merino  wool  should  be  scoured  with  less  alkali  than 
a  comparatively  clean  but  low-grade  Territory  wool,  on  account 
of  the  greater  liability  to  injure  the  fibre  in  the  former  case. 

4.  The  Scouring  of  Woolen  Yarn.  —  As  the  impurities  in  woolen 
yarn  differ  very  materially  from  those  present  in  raw  wool,  we 
would  naturally  expect  a  difference  in  the  manner  of  scouring. 
The  impurities  in  yarn,  in  the  first  place,  are  much  less  in  amount, 
varying  from  10  to  20  per  cent,  in  ordinary  woolen  yarns,  and 
from  2  to  5  per  cent,  with  most  worsted  yarns.     The  character  of 


1 8  DYEING   AND    TEXTILE   CHEMISTRY. 

these  impurities  is  also  different;  they  consist  of  the  oil  which 
has  been  added  during  the  spinning  of  the  wool,  together  with  the 
miscellaneous  dust  and  dirt  it  may  have  collected  passing  through 
the  various  machines  in  carding  and  spinning.  Oil  is  added  to 
wool  for  spinning  in  order  to  make  the  fibres  more  plastic  and  to 
preserve  them  from  mechanical  injury.  Such  oil  should  be 
capable  of  easy  removal  from  the  spun  yarn  and  should  not  add 
any  deleterious  substance  to  the  wool.  For  instance,  the  oil 
should  not  be  of  a  drying  character,  as  it  will  form  resinous 
products  in  the  wool,  the  presence  of  which  would  be  very  disad- 
vantageous; further,  the  oil  should  be  capable  of  ready  emulsion 
so  that  no  difficulty  may  be  experienced  in  scouring  the  yarn. 
Again,  the  oil  should  be  free  from  acidity,  as  otherwise  it  would 
attack  the  card  clothing  and  other  metallic  surfaces  with  which 
the  wool  may  come  in  contact,  not  only  causing  injury  to  the 
machines  but  also  causing  the  wool  to  become  impregnated  with 
iron  compounds,  which  leads  to  many  defects  in  subsequent 
scouring,  bleaching,  and  dyeing.  Owing  to  the  fact  that  the  im- 
purities in  yarn  are  of  less  amount  and  also  more  easily  removed, 
it  is  customary  to  employ  relatively  less  alkali  in  scouring  than  is 
the  case  with  raw  wool.  Whereas,  in  scouring  the  latter  sub- 
stance the  proportion  of  alkali  is  greater  than  that  of  soap,  with 
yarn  scouring  the  proportion  is  just  reversed,  and  more  soap 
than  alkali  is  used;  and  furthermore  the  strength  of  the  scouring 
liquors  is  much  diminished.  The  exact  composition  of  the  scour- 
ing bath,  also,  in  the  case  of  yarn,  must  be  regulated  with  reference 
to  the  amount  of  impurities  in  the  fibre  as  well  as  the  quality  of 
the  fibre  itself.  Worsted  (and  high-class  yarns  in  general)  con- 
taining but  little  oil  and  dirt  are  scoured  in  comparatively  weak 
solutions  containing  a  good  quality  soap  and  a  minimum  amount 
of  alkali  (or  in  some  cases  none  at  all).  With  lower  grade  and 
dirtier  woolen  yarns  the  proportion  of  alkali  is  increased.  The 
temperature  of  the  scouring  bath  for  yarn,  as  with  that  for  raw 
wool,  is  generally  about  140°  F.,  though  with  fine  lustre- wools 
even  this  temperature  is  considerably  reduced.  Occasionally, 
with  very  low  grade  yarns,  such  as  coarse  carpet  yarns  (containing 


SCOURING   THE   TEXTILE  FIBRES.  1 9 

a  variety  of  crude  hair  fibres,  such  as  goat  and  cow  hair,  coarse 
camel  hair,  mixed  with  jute  and  other  vegetable  fibres,  as  well  as 
large  quantities  of  inferior  grease  used  in  spinning) ,  the  tempera- 
ture of  the  scouring  liquor  may  be  much  increased,  in  some  cases 
even  as  high  as  the  boiling  point. 

5.  The  Scouring  of  Yarns  Containing  Iron.  —  In  some  cases 
woolen  yarns  are  liable  to  contain  quite  appreciable  quantities  of 
iron,  which  may  have  been  derived  in  a  variety  of  ways,  such  as 
rusty  cards,  the  use  of  an  acid  oil  in  spinning,  contamination 
with  the  lubricating  oil  on  the  machines,  etc.     Such  yarns  are 
usually  of  a  deep  grayish  color,  and  if  scoured  in  solutions  contain- 
ing soda  ash  (or  potash)  will  usually  come  from  the  scouring  bath 
badly  discolored  by  a  yellowish  brown  stain.     This  is  due  to  the 
iron  becoming  fixed  in  the  fibre  in  the  form  of  iron  oxide  (iron 
rust)  by  reaction  with  the  alkali.     Such  yarn  will  exhibit  serious 
defects  in  subsequent  dyeing,  as  the  iron  will  act  as  a  "mordant" 
for  many  coloring-matters  and  tends  to  dull  or  "sadden"  the 
color.     Yarn  of  this  character  should  be  scoured  in  solutions 
containing  only  soap  without  the  addition  of  any  alkali,  so  as  to 
permit  of  the  proper  removal  of  the  iron  rather  than  its  fixation 
in  the  fibre. 

6.  Soaps   for   Scouring   Wool.  —  A   soap   is   a   combination 
between  an   alkali   and  a  fatty  acid,  and  is  produced  by  the 
action  of  a  caustic  alkali  on  an  oil  or  fat.     The  latter  substances 
(whether  of  vegetable  or  animal  origin)  are  compounds  of  glycerin 
with  various  fatty  acids,  and  by  proper  treatment  with  caustic 
soda  or  caustic  potash  are  decomposed  with  the  liberation  of 
glycerin  and  the  formation  of  a  soap.     Caustic  soda  yields  hard 
soaps,  whereas  caustic  potash  gives  soft  soaps.     The  different  oils 
and  fats,  naturally,  furnish  soaps  of  different  characteristics,  and 
some  soaps  are  more  suitable  for  scouring  than  others.     A  good 
scouring  soap  should  be  readily  soluble  in  water  and  possess  high 
emulsifying  powers  towards  greasy  matters;  it  should  contain  no 
fats  which  would  act  deleteriously  on  the  fibre  or  leave  it  with 
an  objectionable  odor  or  color.     The  soap  should  furthermore  be 
capable  of  easy  removal  from  the  wool  after  scouring,  and  not 


2O  DYEING  AND    TEXTILE  CHEMISTRY. 

leave  behind  any  resinous  or  fatty  matters  of  an  insoluble  char- 
acter. As  already  mentioned,  it  should  also  not  contain  any 
appreciable  quantity  of  free  caustic  alkali;  nor,  on  the  other 
hand,  should  it  contain  unsaponified  fat.  Soaps  made  from 
olive  oil  are  usually  considered  of  the  highest  grade  and  the  most 
desirable  for  wool  scouring;  although  soaps  made  from  cotton- 
seed oil,  maize  oil,  tallow,  oleine  (the  liquid  fat  obtained  as  a 
by-product  in  candle-making),  and  palm  oil  are  also  extensively 
employed.  Often  mixed  soaps  are  used,  such  as  olive  or  cotton- 
seed oil  soap  in  combination  with  a  tallow  soap.  Both  hard  and 
soft  soaps  are  used,  though  the  latter  are  generally  preferred  for 
scouring  raw  wool  as  well  as  yarn. 

7.  Relation  of  Water  to  Wool  Scouring.  —  The  use  of  the 
proper  kind  of  water  in  wool  scouring,  both  for  the  preparation 
of  the  scouring  bath  and  for  the  washing  of  the  wool  after  scour- 
ing, is  a  matter  of  considerable  importance.  The  use  of  hard 
water,  as  such,  should  be  interdicted,  on  account  of  its  bad  action 
with  soap  solutions.  By  a  " hard"  water  is  meant  one  containing 
considerable  amounts  of  dissolved  mineral  substances,  usually 
compounds  of  calcium  (lime),  magnesium,  and  sometimes  iron. 
These  mineral  substances  in  solution  combine  with  soap  to  form 
insoluble  and  sticky  precipitates,  which  cause  not  only  a  loss  of 
soap  and  a  consequent  decrease  in  the  scouring  power  of  the 
bath,  but  also  these  precipitates  adhere  to  the  fibre  and  are 
difficult  of  removal.  Sometimes  the  " hardness"  of  water  is 
removable  by  simply  boiling;  it  is  then  termed  temporary  hard- 
ness, and  is  principally  due  to  the  presence  of  carbonic  acid  gas 
holding  calcium  carbonate  (limestone)  in  solution.  On  boiling, 
the  carbonic  acid  gas  is  driven  off  and  in  consequence  the  calcium 
carbonate  is  precipitated.  Permanent  hardness,  on  the  other 
hand,  is  not  removable  by  boiling,  and  is  chiefly  due  to  the 
presence  of  calcium  sulphate  (gypsum).  To  remove  hardness 
of  this  character  soda  ash  is  usually  added  sufficient  to  precipi- 
tate the  calcium  compound  as  the  highly  insoluble  carbonate. 
Or,  small  quantities  of  oxalic  acid  and  ammonia  may  be  added, 
which  causes  the  precipitation  of  the  lime  as  calcium  oxalate. 


SCOURING   THE   TEXTILE  FIBRES.  21 

Before  hard  water  is  used  in  connection  with  wool  scouring  it 
should  be  "corrected"  in  one  of  the  ways  here  indicated.  Water 
containing  any  appreciable  amount  of  iron  is  especially  objec- 
tionable for  use  in  scouring,  as  the  iron  readily  becomes  firmly 
fixed  in  the  fibre,  leading  to  many  bad  defects.  Iron  may  be 
best  removed  from  water  by  proper  aeration  and  filtration. 
Should  the  water  contain  sediment  in  any  appreciable  amount  it 
should  be  properly  filtered  before  use.  River  or  pond  water  is 
liable  to  contain  a  larger  amount  of  sediment  than  spring  or  well 
water,  but,  on  the  other  hand,  as  a  rule,  its  hardness  is  not  so 
great,  nor  is  it  as  liable  to  contain  iron. 

8.  Boiling-out  of  Cotton.  —  Raw  cotton  is  unlike  wool  in 
that  it  contains  a  relatively  small  amount  of  natural  impurity, 
and  for  many  purposes  cotton  is  not  scoured  at  all.  Whereas 
raw  wool  cannot  be  manufactured  into  yarn  without  a  previous 
removal  of  its  greasy  and  dirty  matters,  cotton  is  spun  without 
any  such  preliminary  cleansing  being  required;  in  fact  the 
impurity  that  is  present  in  raw  cotton  is  an  aid  rather  than  a 
hindrance  to  the  proper  spinning  of  this  fibre.  In  many  cases 
of  dyeing,  also,  a  previous  scouring  of  cotton  is  not  required. 
The  impurities  in  raw  cotton  consist  for  the  most  part  of  waxy 
and  resinous  matters,  which  are  classified  under  the  general 
term  of  pectin  substances.  These  amount  to  about  5  per  cent, 
on  the  weight  of  the  fibre.  By  reason  of  its  coating  of  waxy 
matters,  the  cotton  fibre  is  more  or  less  waterproof,  or  rather 
water-repellent,  and  will  not  readily  "wet-out"  when  placed 
in  water.  This  property  is  frequently  a  drawback  in  dyeing, 
as  the  dye  solution  will  not  penetrate  perfectly  and  evenly.  To 
overcome  this  defect  it  is  necessary  to  remove  the  waxy  coating 
on  the  cotton,  and  this  is  best  done  by  boiling  in  a  solution  of 
caustic  soda,  soda  ash,  or  soap,  or  with  some  oil  which  has  the 
property  of  dissolving  the  cotton-wax.  This  "  wetting-out "  of 
cotton  for  purposes  of  dyeing  or  mordanting  is  simply  with  a 
view  of  allowing  it  to  become  quickly  and  thoroughly  saturated 
with  the  solutions  in  which  it  may  be  placed.  When  cotton  is  to 
be  bleached,  however,  it  is  not  only  necessary  to  scour  the  fibre 


22  DYEING   AND    TEXTILE   CHEMISTRY. 

so  that  it  will  readily  wet-out,  but  also  to  completely  remove 
all  resinous  substances,  otherwise  a  good  clear  white  will  not  be 
obtained  in  the  bleaching.  For  this  purpose,  it  is  generally 
necessary  to  boil  the  cotton  with  a  solution  of  caustic  soda  (or 
other  alkalies)  for  a  number  of  hours  and  usually  under  more  or 
less  pressure.  This  operation  is  termed  "  boiling-out "  to  dis- 
tinguish from  mere  "  wetting-out.'*  In  the  scouring  of  cotton 
it  is  probable  that  the  waxy  and  resinous  substances  in  the 
fibre  are  emulsified  or  dissolved.  Caustic  soda  is  probably  the 
most  generally  employed  chemical  for  the  scouring  of  cotton, 
though  soda  ash  and  sodium  silicate  are  also  extensively  used. 
Often  mixtures  of  these  three  are  employed.  Soap  is  also  an 
efficient  medium  for  wetting-out  cotton,  though  it  appears  that 
when  a  very  thorough  boiling-out  process  is  required  a  more 
strongly  alkaline  agent  is  desirable.  Formerly  lime  [  (slaked  in 
water)  was  extensively  employed  for  boiling-out  cotton  pre- 
liminary to  bleaching,  but  its  use  is  rapidly  giving  way  to  that 
of  caustic  soda.  Certain  so-called  "soluble  oils"  (prepared  by 
treating  castor  oil,  cotton-seed  oil,  etc.,  with  strong  sulphuric 
acid,  and  hence  also  called  "sulphated"  oils)  appear  to  possess 
the  property  of  quickly  dissolving  the  waxy  matters  from  cotton, 
and  these  are  sometimes  used  for  the  purpose  of  wetting-out  of 
cotton  for  dyeing.  They  are  also  at  times  used  in  the  process  of 
boiling-out.  Fankhausine,  Solvine,  Monopol  Oil,  etc.,  are  com- 
pounds of  this  character,  and  consist,  for  the  most  part,  of  sul- 
phated vegetable  oils.  For  the  purpose  of  merely  wetting-out  it 
is  probably  better  to  use  either  a  solution  of  soap  or  a  soluble 
oil,  rather  than  the  alkalies,  as  the  former  method  leaves  the 
cotton  somewhat  whiter  in  appearance  and  softer  in  feel.  It  is 
probable  that  when  boiled  with  solutions  of  caustic  soda  or  soda 
ash  the  resinous  matters  in  the  fibre  are  decomposed  with  the 
formation  of  brown  coloring-matters,  and  as  a  result  the  cotton 
has  a  darker  color  than  when  treated  with  soap  or  oil. 

9.  The  Impurities  in  Raw  Silk.  —  Raw  silk,  as  it  appears  in 
trade,  does  not  much  resemble  the  brilliant  and  lustrous  fibre 
seen  in  manufactured  silk  fabrics.  Raw  silk  consists  not  only 


SCOURING   THE    TEXTILE  FIBRES.  23 

of  the  fibre  proper,  but  also  of  a  large  amount  of  a  glue-like  sub- 
stance which  heavily  coats  the  fibre  and  gives  it  a  harsh,  brittle 
feel  and  hides  the  lustre  and  whiteness  of  the  true  fibre.  This 
substance  is  known  as  silk-glue  or  sericin,  and  it  amounts  to 
about  25  per  cent,  of  the  weight  of  the  raw  silk.  It  is  soluble' in 
water,  and  may  indeed  be  completely  removed  from  the  fibre 
by  prolonged  boiling.  It  is,  however,  more  readily  removed  by 
strong  solutions  of  soap,  and  this  is  the  usual  method  employed. 
The  fibre  proper  of  silk  is  known  as  fibroin,  and  though  very 
similar  in  chemical  composition  to  sericin,  it  is  insoluble  in 
water  or  soap  solutions.  The  most  of  the  coloring-matter 
in  raw  silk  is  also  contained  in  the  silk-glue  and  is  removed 
along  with  this  latter  substance.  Certain  raw  silks  (yellow-gum 
Italian  for  instance)  are  of  a  deep  yellow  color,  but  when  com- 
pletely stripped  of  silk-glue  they  become  as  white  as  other  silks. 
10.  The  Boiling-off  of  Silk.  —  The  scouring  of  raw  silk,  or  the 
removal  from  it  of  the  silk-glue,  is  usually  termed  "boiling-off," 
though  the  expressions  "degumming"  and  " stripping"  are 
also  used.  When  completely  boiled-off  silk  will  lose  in  weight 
from  22  to  28  per  cent.  Frequently,  however,  all  of  the  silk- 
glue  is  not  removed,  but  only  sufficient  to  make  it  soft  and 
lustrous  and  workable  in  dyeing  or  bleaching.  Under  these 
circumstances,  the  scouring  of  silk  is  termed  soupling,  and 
only  from  10  to  15  per  cent,  in  weight  is  lost.  Furthermore, 
raw  silk  is  sometimes  given  only  a  very  slight  scouring  for  the 
purpose  of  softening  the  fibre;  this  gives  what  is  called  ecru 
silk,  and  only  2  to  5  per  cent,  in  weight  of  the  silk-glue  is  removed. 
The  scouring  of  silk  is  almost  invariably  accomplished  by  the  use 
of  boiling  solutions  of  soap.  The  length  of  time  and  the  number 
of  soapings  given  will  determine  how  much  of  the  sericin  will 
be  removed.  For  a  complete  boiling-off  a  strong  soap  solution  is 
necessary  (about  one  pound  of  soap  per  gallon),  and  the  time 
required  is  from  i  to  2  hours,  and  this  treatment  is  usually 
repeated  with  a  second  soap  solution.  The  soap  employed  for 
the  scouring  of  silk  should  be  of  the  very  best  quality,  and  should 
be  as  neutral  as  possible.  The  presence  of  any  appreciable 


24  DYEING  AND    TEXTILE  CHEMISTRY. 

free  alkali  in  the  scouring  bath  will  rapidly  injure  the  silk  fibre, 
causing  it  to  become  weakened,  discolored,  and  lustreless. 
Generally,  the  best  grade  of  hard  olive  oil  soap  is  used;  soft 
soaps  are  not  employed  because  these  are  nearly  always  liable  to 
contain  small  quantities  of  free  alkali.  The  scouring  baths  left 
after  the  boiling-off  of  silk  (and  usually  repeated  lots  of  raw 
silk  are  scoured  in  the  same  soap  solution)  contain  a  large 
quantity  of  silk-glue  together  with  the  soap  employed.  These 
residual  baths  are  known  as  boiled-off  liquors  and  are  exten- 
sively used  as  an  adjunct  in  the  dyeing  of  silk,  being  added  in 
considerable  amount  to  the  dye-bath  for  the  purpose  of  softening 
the  dyed  silk  and  promoting  the  even  distribution  of  the  color. 
After  the  silk  has  been  scoured  or  boiled-off  it  should  be  thor- 
oughly washed  with  water  in  order  to  remove  all  trace  of  soapy 
liquor,  otherwise  the  soap  will  dry  into  the  fibre  and  cause  dis- 
colorations  and  imperfections.  After  the  scoured  silk  is  dried, 
in  order  to  soften  the  fibre  and  to  give  it  increased  lustre,  it  is 
stretched  or  steamed.  This  is  merely  a  mechanical  treatment 
which  loosens  up  the  fine  and  delicate  filaments  of  the  silk  fibre 
which  have  become  more  or  less  matted  together  in  the  scouring 

and  drying. 

SAMPLES. 

22.  Raw  wool  in  the  grease. 

23.  Wool  scoured  with  soap  and  soda  ash. 

24.  Wool  scoured  with  soap  and  potash. 

25.  Wool  scoured  at  a  boiling  temperature. 

26.  Wool  scoured  with  excessive  alkali. 

27.  Woolen  yarn  in  the  grease. 

28.  Woolen  yarn  scoured. 

29.  Woolen  yarn  containing  iron  in  the  grease. 

30.  Woolen  yarn  containing  iron  scoured  with  soda  ash. 

3 1 .  Woolen  yarn  containing  iron  scoured  with  soap  alone. 

32.  Cotton  yarn;  unsecured. 

33.  Cotton  yarn  scoured  with  caustic  soda. 

34-  Cotton  yarn  scoured  with  soda  ash. 

35-  Cotton  yarn  scoured  with  soap. 

36.  Cotton  yarn  scoured  with  Fankhausine. 

37-  Raw  silk  in  the  gum. 

38.  Boiled-off  silk. 

39-  Boiled-off  silk  after  stretching. 


SCOURING    THE   TEXTILE  FIBRES. 
RECORD    OF  RESULTS. 


Test. 

Weight  before 
scouring. 

Weight  after 
scouring. 

Loss  in 
weight. 

Shrinkage. 
Per  cent. 

6  

7 

8 

9. 

10  

1  3 

id. 

I  r 

X6     

QUIZ  2. 

27.  Describe  the  general  character  of  the  different  impurities  existing  in 
raw  wool. 

28.  How  does  wool  grease  differ  from  other  animal  fats  in  its  chemical 
composition?    How  does  wool  grease  react  with  water  and  alkaline  or  soap 
solutions? 

29.  What  is  suint  and  of  what  does  it  consist?     Is  it  soluble  or  insoluble  in 
water? 

30.  What  chemicals  are  employed  in  the  usual  method  of  wool  scouring? 
At  what  temperature  is  the  scouring  operation  conducted  ? 

31.  Why  is  it  necessary  that  the  soap  and  alkali  employed  in  wool  scouring 
should  be  as  free  as  possible  from  caustic  alkali  ? 

32.  Why  is  it  necessary  to  wash  the  wool  thoroughly  after  scouring,  and 
why  is  warm  water  employed  ? 

33.  What  percentage  of  impurities  is  present  in  raw  wool?     Is  this  amount 
at  all  constant  for  different  wools?     How  does  the  amount  of  grease  in  fine 
wools  compare  with  that  present  in  coarse  wools  ? 

34.  What  is  meant  by  the  shrinkage  of  raw  wool  ?    Why  is  it  important  for 
the  wool  buyer  to  know  this  factor  ? 

35.  Based  on  the  quantities  given  in  the  test,  how  many  pounds  of  soap 
and  soda  ash  would  be  required  to  prepare  a  scouring  bath  containing  1000 
gallons  of  water? 


26  DYEING  AND    TEXTILE   CHEMISTRY. 

36.  .What  is  potash?     Why  is  its  use  for  wool  scouring  recommended  in 
place  of  soda  ash  ?     How  did  your  results  in  scouring  with  the  two  compare  ? 

37.  Why  is  wool  not  scoured  at  temperatures  above  140°  F.  ?    What  is 
the  effect  of  scouring  at  the  boil  ?     How  does  the  sample  of  wool  scoured  at  the 
boil  compare  with  samples  scoured  at  lower  temperatures? 

38.  What  is  the  effect  of  employing  an  excessive  amount  of  alkali  in  the 
scouring  bath  ? 

39.  How  does  the  general  method  of  scouring  woolen  yarn  differ  from  that 
of  scouring  raw  wool  with  respect  to  the  relative  proportions  of  soap  and 
alkali? 

40.  Describe  the  general  nature  of  the  impurities  in  woolen  yarn.     Why  is 
wool  oiled  in  spinning,  and  what  should  be  the  character  of  the  oils  employed  ? 

41.  Why  is  some  woolen  yarn  liable  to  contain  iron  in  the  grease?     How 
should  yarn  of  this  character  be  scoured?    Why  should  soda  ash  not  be 
employed  ? 

42.  What  is  the  general  nature  of  the  impurities  existing  in  raw  cotton? 
What  is  their  average  amount  ? 

43.  Why  is  it  necessary  to  scour  cotton  before  dyeing  or  bleaching?     Is  a 
previous  scouring  always  required  before  dyeing  ? 

44.  How  does  the  " wetting-out"  differ  from  the  "boiling-out"  of  cotton? 

45.  What  is  the  general  principle  involved  in  the  scouring  of  cotton  ?    What 
chemicals  may  be  employed  for  this  purpose  ? 

46.  Give  a  comparison  of  the  results  obtained  in  the  boiling-out  of  cotton 
with  caustic  soda,  soda  ash,  and  soap.     About  how  much  does  cotton  lose  in 
weight  by  boiling-out  ? 

47.  What  is  Fankhausine?    How  does  it  act  in  the  scouring  of  cotton? 
How  does  cotton  boiled-out  with  Fankhausine  compare  with  that  boiled-out 
with  alkalies  ? 

48.  What  substances  are  present  in  raw  silk?    In  what  relative  amounts 
do  these  exist? 

49.  How  does  sericin  differ  from  fibroin?    How  does  raw  silk  differ  in  its 
general  appearance  from  boiled-off  silk  ? 

50.  What  substance  is  removed  in  the  scouring  of  silk?     By  what  dif- 
ferent names  is  the  scouring  of  silk  known?    How  much  does  silk  lose  in 
weight  by  scouring  ? 

5 1 .  How  is  the  boiling-off  of  silk  conducted  ?    What  chemicals  are  employed 
and  at  what  temperature  ? 

52.  What  kind  of  soap  should  be  employed  for  boiling-off  silk?    Why 
should  the  soap  be  as  neutral  as  possible  ? 

53.  What  strength  of  soap  solution  is  employed  for  boiling-off  silk?     On 
the  basis  of  the  figures  given  in  the  experiment,  how  many  pounds  of  soap 
would  be  required  to  make  up  100  gallons  of  liquor  for  scouring  silk  ? 


SCOURING    THE    TEXTILE  FIBRES.  2/ 

54.  What  is  the  difference  between  "ecru,"  "soupled,"  and  "boiled-off" 
silk? 

55.  Does  the  complete  removal  of  the  silk  gum  from  raw  silk  generally  take 
place  in  a  single  scouring  bath  ? 

56.  How  is  the  boiled-off  silk  softened  and  lustred?    In  what  constituent 
of  raw  silk  does  the  natural  coloring-matter  principally  occur,  and  is  it  removed 
in  the  boiling-off? 

57.  What  is  meant  by  "boiled-off  liquor"?     Of  what  does  it  consist?     For 
what  purpose  is  it  employed  ? 


SECTION   III. 
BLEACHING  OF  WOOL. 

Experiment  17.  Bleaching  Wool  by  Tinting.  —  Take  a  well- 
scoured  test-skein  of  woolen  yarn  (40),  and  work  in  a  luke- 
warm bath  containing  a  trace  of  oxalic  acid  and  a  trace  of 
Acid  Violet  2  B  (about  ?fo  per  cent,  on  the  weight  of  the  wool 
will  as  a  rule  be  ample  dyestuff).  Take  great  care  not  to  add 
too  much  of  the  coloring-matter,  otherwise  too  distinct  a  color 
will  be  imparted  to  the  wool.  After  tinting,  squeeze  and  dry  (41). 
It  will  be  found  that  the  violet  coloring-matter  has  neutralized  the 
yellowish  tint  of  the  wool,  so  that  the  material  seems  whiter  than 
before.  To  show  the  same  operation  on  cotton,  take  a  test- 
skein  of  cotton  yarn  (42)  which  has  been  well  scoured  out  with 
2  per  cent,  of  Monopol  Soap,  and  work  it  in  a  dilute  lukewarm 
soap  bath  containing  a  trace  (about  -s^u  per  cent,  on  the  weight 
of  the  cotton)  of  Methyl  Violet  5  B.  Then  squeeze  and  dry  (43). 
It  will  be  found  that,  as  with  the  wool,  the  skein  of  cotton  will 
appear  whiter  after  tinting,  owing  to  the  fact  that  the  violet-blue 
color  has  destroyed  the  yellowish  color  of  the  natural  fibre. 

Experiment  18.  Bleaching  Wool  with  Sulphurous  Acid  Gas.  — 
Take  a  skein  of  well-scoured  woolen  yarn,  wet  it  out  in  water, 
then  squeeze  it  so  that  the  wool  is  left  only  moist;  place  it  in  a 
compartment  filled  with  sulphurous  acid  gas  for  12  to  24  hours. 
Then  wash  well  in  water,  and  then  in  a  bath  containing  a  trace 
of  oxalic  acid  and  Acid  Violet  for  tinting  (44). 

Experiment  19.  Bleaching  Wool  with  Sodium  Bisulphite. — 
Prepare  a  bath  containing  300  cc.  of  water  and  10  cc.  of  sodium 
bisulphite  solution  (32°Tw.).  Immerse  two  well- scoured  skeins 
of  woolen  yarn  in  this  bath,  work  well  for  about  15  minutes, 
then  allow  to  soak  for  12  to  24  hours.  Then  squeeze  and  work 
in  a  bath  containing  5  per  cent,  of  sulphuric  acid  (on  the  weight 

28 


BLEACHING  OF   WOOL.  29 

of  the  wool).  Then  wash  the  first  skein  well  in  water,  and 
finally  in  a  bath  containing  a  trace  of  oxalic  acid  and  Acid  Violet 
for  tinting.  Then  squeeze  and  dry  (45).  Take  the  second  skein 
so  bleached  and  pass  through  a  cold  bath  containing  a  couple  of 
drops  of  a  dilute  solution  of  potassium  permanganate  (just 
sufficient  to  give  the  water  a  violet  color),  and  then  wash  again 
(46).  If  too  strong  a  solution  of  the  potassium  permanganate 
is  used  the  wool  will  acquire  a  brownish  color,  and  will  have 
to  be  passed  through  a  dilute  bath  of  sodium  bisulphite  in 
order  to  remove  the  brown  hydrate  of  manganese  which  will 
be  precipitated  on  the  fibre.  Cut  about  6  inches  from  each 
of  the  two  bleached  skeins  and  plait  with  portions  of  a  skein  of 
woolen  yarn  which  has  been  dyed  with  Magenta  (a  dyestuff 
quite  susceptible  to  the  action  of  sulphurous  acid),  and  allow 
the  samples  thus  prepared  to  remain  for  several  days.  The 
skein  of  dyed  yarn  may  easily  be  prepared  by  working  a  skein 
of  woolen  yarn  in  a  bath  containing  300  cc.  of  water  and  about 
5  cc.  of  a  solution  of  Magenta  for  one-half  hour  at  a  temperature 
of  1 80°  F.  On  examination  after  a  time  it  will  be  found  that 
the  bleached  skein  which  was  not  treated  with  the  potassium 
permanganate  solution  has  caused  a  discoloration  of  the  dyed 
sample  with  which  it  was  plaited  (47) ,  whereas  the  other  bleached 
skein  has  not  (48) .  This  test  shows  the  presence  of  sulphurous 
acid  in  the  former  and  the  absence  of  it  in  the  latter. 

Experiment  20.  Bleaching  Wool  with  Sodium  Peroxide.  — 
Prepare  a  bath  containing  300  cc.  of  water  and  3  cc.  of  concen- 
trated sulphuric  acid;  then  carefully  add  with  constant  stirring, 
4  grams  of  sodium  peroxide.  Test  with  litmus  paper,  and  if  not 
acid  in  reaction,  add  sufficient  dilute  sulphuric  acid  to  turn  the 
paper  red.  This  will  neutralize  all  of  the  caustic  soda  formed  in 
the  decomposition  of  the  sodium  peroxide  with  the  water.  Now 
add  sufficient  sodium  silicate  solution  to  make  the  bath  slightly 
alkaline;  that  is,  until  it  turns  the  litmus  paper  blue  again.  Heat 
the  bath  to  120°  F.,  when  it  is  ready  for  bleaching.  Take  a  well- 
scoured  skein  of  woolen  yarn  and  work  it  in  this  bath  for  15 
minutes,  and  then  allow  it  to  steep  under  the  liquor  for  12  to  15 


3O  DYEING   AND    TEXTILE   CHEMISTRY. 

hours,  maintaining  the  temperature  as  nearly  as  possible  at  about 
100°  F.  during  that  time.  Then  wash  well  and  squeeze,  and 
finally  tint  in  a  bath  containing  a  trace  of  oxalic  acid  and  Acid 
Violet.  Then  squeeze  and  dry  (49). 

Experiment  21.  Bleaching  Wool  with  Potassium  Permanga- 
nate. —  Prepare  a  bath  containing  300  cc.  of  water  and  0.2  gram 
of  potassium  permanganate  and  5  per  cent,  (on  the  weight  of 
the  wool)  of  sulphuric  acid.  Warm  the  bath  to  100°  F.,  and 
steep  a  well-scoured  skein  of  woolen  yarn  therein  for  about 
5  minutes,  working  during  that  time.  Then  rinse,  and  it  will  be 
found  that  the  wool  has  become  brown  in  color  (50) ;  this  is  due 
to  the  precipitation  of  hydrated  oxide  of  manganese  on  the  fibre, 
resulting  from  the  decomposition  of  the  potassium  permanganate. 
Next  work  the  skein  in  a  cold  bath  containing  300  cc.  of  water 
and  2  cc.  of  sodium  bisulphite  solution  (of  32°  Tw.).  The  wool 
will  rapidly  turn  white  (51),  as  the  brown  deposit  of  manganese 
oxide  is  dissolved  by  the  bisulphite  of  soda. 

NOTES. 

i.  Bleaching  Wool.  —  The  wool  fibre  in  its  natural  condition 
always  contains  some  pigment  matter;  even  the  usual  so-called 
"  white"  wool  contains  a  small  amount  of  a  yellowish  brown  color 
which  it  is  necessary  to  remove  in  order  to  have  a  fibre  possessing 
a  clear  white  color.  In  some  grades  of  wool  the  amount  of 
pigment  matter  may  be  comparatively  large,  giving  the  brown  or 
black  wools.  These  wools,  however,  are  small  in  amount  com- 
pared with  the  white  wools  and  are  seldom,  if  ever,  bleached. 
The  method  of  bleaching  wool  by  the  tinting  process  described 
in  Exp.  17  depends  on  the  neutralization  of  the  slight  yellow  tint 
of  the  natural  wool  by  dyeing  the  fibre  with  a  delicate  tint  of 
blue  or  violet  coloring-matter.  It  is  not  really  a  removal  or 
destruction  of  the  natural  pigment,  but  simply  a  change  of  the 
yellow  tint  to  one  of  a  grayish  tone.  The  latter  being  less  sus- 
ceptible to  the  eye  causes  the  wool  to  appear  white.  The  color 
relations  in  the  case  are  based  on  the  fact  that  yellow  and  violet 
are  complementary  colors,  so  that  when  mixed  in  small  amount 


BLEACHING   OF   WOOL.  31 

they  produce  gray.  For  the  tinting  color  it  is  best  to  use  a  blue 
dyestuff  with  a  slight  violet  tone,  such  as  a  very  blue  tone  of 
Acid  Violet.  Oxalic  acid  is  used  with  the  dyestuff  to  render  the 
solution  slightly  acid  and  thus  develop  the  color.  The  actual 
amount  of  color  required  is  very  small  and  care  must  be  exercised 
not  to  overtint  the  wool,  or  a  bluish  tone  will  be  obtained.  Wool 
bleached  in  this  manner,  of  course,  will  not  possess  as  clear  a 
white  color  as  that  in  which  the  natural  pigment  is  actually 
destroyed;  it  will  only  give  a  dull,  cloudy-looking  white. 

Sulphurous  acid,  or  one  of  its  compounds,  is  the  agent  mostly 
employed  for  the  true  bleaching  of  wool.  Sulphurous  acid  is  a 
strong  reducing  agent;  that  is  to  say,  it  has  a  strong  "  affinity " 
for  oxygen.  When  acting  on  many  organic  coloring-matters 
(such  as  the  natural  pigment  in  wool)  it  "reduces"  them,  thus 
causing  them  to  be  converted  into  colorless  substances.  Many 
coloring-matters,  however,  after  being  thus  reduced,  are  capable 
of  becoming  oxidized  on  exposure  to  air  so  as  to  yield  again  the 
original  color;  this  appears  to  be  the  case  with  the  coloring-matter 
in  wool,  for  when  bleached  with  sulphurous  acid  the  yellow  tint 
becomes  gradually  restored  on  exposure  to  the  air. 

Bleaching  by  the  use  of  sulphurous  acid  gas  is  the  method 
mostly  practiced  for  the  bleaching  of  wool.  The  process  is 
rather  simple;  the  wool  (either  in  loose  state,  yarn,  or  cloth)  is 
moistened  and  spread  out  or  hung  in  a  room  where  it  is  subjected 
to  the  action  of  the  sulphurous  acid  gas  for  10  to  20  hours.  The 
gas  is  produced  generally  by  the  burning  of  sulphur  in  an  iron 
or  earthenware  pot,  sometimes  in  the  bleaching  room  itself, 
though  it  is  considered  better  to  burn  the  sulphur  in  an  apparatus 
outside  the  bleaching  room  and  to  lead  the  gas  into  the  latter. 
From  the  use  of  the  so-called  "stove"  for  burning  the  sulphur, 
this  process  of  bleaching  has  received  the  name  of  "stoving." 
The  wool  (in  whatever  form)  must  be  thoroughly  scoured  for 
bleaching  and  should  be  in  a  moist  (though  not  wet)  condition, 
as  the  gas  acts  but  slowly  on  the  dry  wool.  The  material  should 
also  be  so  distributed  in  the  bleaching  room  that  the  gas  may 
easily  come  in  contact  with  all  parts  of  the  fibre.  Usually  the 


OF  THE 

UNIVERSITY 


fSN 

ITV      1 


32  DYEING   AND    TEXTILE   CHEMISTRY. 

gas  is  allowed  to  pass  from  one  end  of  the  room  to  the  other  and 
thence  out  through  a  flue.  The  bleaching  chamber  must  be  so 
constructed  that  the  condensed  vapors  (which  consist  of  rather 
concentrated  sulphuric  acid)  cannot  drop  on  the  wool,  else  spotting 
will  result,  or  the  fibre  may  even  be  seriously  injured.  Also  the 
room  should  not  contain  exposed  iron  parts  which  may  come  in 
contact  with  the  sulphur  gas,  as  the  metal  will  rapidly  be  attacked 
and  the  condensed  drops  that  may  fall  on  the  wool  will  cause  bad 
spotting. 

2.  .Use  of  Sodium  Bisulphite.  —  The  use  of  this  chemical  for 
the  bleaching  of  wool  is  merely  a  convenient  method  for  the 
application  of  sulphurous  acid  in  the  form  of  a  solution.  The 
bleaching  agent,  in  fact,  is  exactly  the  same  as  when  sulphurous 
acid  gas  is  employed,  and  the  character  of  the  bleach  obtained  in 
the  two  cases  is  practically  identical.  Sodium  bisulphite  has  the 
chemical  formula  NaHSO3,  and  when  dissolved  in  water  its 
solution  practically  consists  of  sodium  sulphite  and  sulphurous 
acid: 

2  NaHSO3  =  Na2SO3  +  H2SO3. 

When  wool  is  steeped  in  this  solution  the  sulphurous  acid  acts 
directly  upon  the  fibre  as  a  bleaching  agent,  and  moreover,  the 
wool  also  becomes  saturated  with  the  sodium  sulphite.  Hence 
the  wool  is  subsequently  treated  with  a  solution  of  sulphuric  acid, 
which  reacts  with  the  sodium  sulphite,  forming  sodium  sulphate 
and  liberating  another  portion  of  sulphurous  acid: 

Na2S03  +  H2S04  =  Na^SO,  +  H2SO3. 

This  second  portion  of  sulphurous  acid  also  aids  materially  in 
the  bleaching  of  the  wool. 

Bleached  wool  is  usually  tinted  with  a  blue  or  bluish  violet 
coloring-matter  in  order  to  give  to  the  fibre  a  bluish  white  tone 
which  is  more  pleasing  to  the  eye  than  the  flat  bleach.  A  minute 
quantity  of  a  blue  shade  of  Acid  Violet  is  useful  for  this  purpose, 
and  it  is  generally  applied  in  the  rinsing  bath  after  the  bleaching, 
adding  a  small  quantity  of  oxalic  acid  to  the  water  for  the  purpose 


BLEACHING  OF   WOOL.  33 

of  developing  the  color  and  also  for  the  purpose  of  removing 
any  trace  of  brownish  stain  due  to  the  presence  of  iron  com- 
pounds. 

Mention  has  already  been  made  of  the  fact  that  the  bleach 
obtained  on  wool  by  means  of  sulphurous  acid  is  not  a  permanent 
one,  but  the  yellow  tint  reappears  after  prolonged  exposure  to  the 
air.  Furthermore,  it  appears  to  be  practically  impossible  to 
remove  every  trace  of  sulphurous  acid  from  the  fibre,  however 
thorough  the  washing  may  be  after  the  bleaching.  The  wool 
apparently  combines  in  a  chemical  manner  with  the  sulphurous 
acid,  and  this  leads  to  two  defects  in  the  bleached  wool;  in  the 
first  place,  the  presence  of  the  sulphurous  acid  apparently  holds 
the  pigment  in  the  fibre  in  a  reduced  state  so  that  the  bleach  lacks 
permanency  of  character,  as  already  noted ;  secondly,  the  presence 
of  the  sulphurous  acid  is  liable  to  act  injuriously  on  other  dyed 
colors  with  which  the  bleached  wool  may  subsequently  come  in 
contact  when  woven  into  cloth.  This  effect  is  illustrated  in  the 
experiment  by  the  action  of  the  bleached  wool  in  contact  with 
wool  dyed  with  Magenta.  For  these  reasons  it  has  long  been 
recognized  as  desirable  to  remove  from  the  bleached  wool  all 
trace  of  sulphurous  acid.  This  may  readily  be  accomplished  by 
treating  the  bleached  material  with  a  solution  containing  a  suit- 
able oxidizing  agent.  Potassium  permanganate  has  been  quite 
extensively  employed  for  this  purpose.  By  its  action  the  sul- 
phurous acid  is  converted  into  sulphuric  acid,  which  is  harmless 
as  far  as  the  effects  outlined  above  are  concerned.  In  the  use  of 
this  agent,  however,  great  care  must  be  exercised  not  to  employ 
an  excess  beyond  that  needed  to  react  with  the  sulphurous  acid, 
otherwise  a  brown  deposit  of  an  oxide  (or  hydrate)  of  manganese 
will  be  left  on  the  wool,  and  a  subsequent  treatment  with  a  solu- 
tion of  sodium  bisulphite  will  have  to  be  given  to  remove  this 
deposit.  Instead  of  using  potassium  permanganate  in  this  con- 
nection it  would  probably  be  better  to  employ  a  small  quantity  of 
sodium  peroxide,  which  would  have  the  same  effect  on  the  trace 
of  sulphurous  acid  without  the  attendant  defect  of  discoloration 
through  the  addition  of  an  excess  of  the  reagent.  The  presence  of 


34  DYEING   AND    TEXTILE   CHEMISTRY. 

traces  of  sulphurous  acid  in  wool  may  be  conveniently  detected 
by  wetting  the  wool  in  a  small  quantity  of  water  and  adding 
a  few  drops  of  a  mixture  of  iodic  acid  and  starch  solutions; 
if  sulphurous  acid  is  present  a  violet  or  blue  color  will  be 
formed. 

3.  Bleaching  Wool  with  Peroxides.  —  The  use  of  sodium 
peroxide  as  a  bleaching  agent  for  wool  is  fast  becoming  of  con- 
siderable practical  importance.  Formerly  hydrogen  peroxide 
was  somewhat  employed  for  this  purpose,  but  its  high  cost  was  a 
bar  to  its  extensive  application.  The  bleaching  action  of  these 
two  substances,  however,  is  identical,  and  is  due  to  the  nascent 
oxygen  which  they  are  capable  of  liberating.  Hydrogen  peroxide 
has  the  chemical  formula  H2O2,  and  is  prepared  by  the  action  of 
sulphuric  acid  on  barium  peroxide.  As  employed  in  the  arts  it 
consists  of  a  comparatively  dilute  solution  (about  3  per  cent.)  of 
hydrogen  peroxide  in  water.  The  chemical  formula  of  sodium 
peroxide  is  Na2O2;  it  is  prepared  by  heating  metallic  sodium  in 
air.  It  occurs  as  a  yellowish  white  powder  and  may  be  obtained 
of  a  high  degree  of  purity.  Some  care  must  be  taken  in  the 
handling  and  using  of  sodium  peroxide,  as  it  is  easily  decomposed 
in  the  presence  of  moisture  and  organic  matter  with  the  evolution 
of  large  volumes  of  oxygen  which  may  lead  to  explosions  or  fires. 
When  handled  with  intelligent  precaution,  however,  it  is  by  no 
means  a  dangerous  chemical.  It  should  be  stored  in  a  cool, 
dry  place  in  comparatively  small  tins  (the  usual  commercial  size 
is  that  containing  10  pounds),  and  should  be  kept  from  contact 
with  water  or  with  organic  matter  such  as  paper,  excelsior,  etc. 
As  the  reaction  which  occurs  between  sodium  peroxide  and  water 
is  a  very  violent  one,  its  solution  should  be  carefully  undertaken. 
Large  quantities  or  lumps  of  sodium  peroxide  should  never  be 
added  to  water,  as  an  explosion  or  fire  is  liable  to  result.  The 
peroxide  should  be  sifted  gradually  into  the  water  with  constant 
stirring.  When  sodium  peroxide  is  dissolved  in  water  caustic 
soda  and  hydrogen  peroxide  are  formed: 

Na2O2+  2  H2O  =  2  NaOH  +  H2O2. 


BLEACHING   OF   WOOL.  35 

Its  bleaching  effect  is  due  to  the  ready  decomposition  of  the 
hydrogen  peroxide  in  contact  with  organic  matter  (such  as  wool) : 

H2O2=  H2O  +  O. 

The  oxygen,  at  the  moment  of  its  liberation  in  such  a  manner,  is 
especially  reactive  (so-called  nascent  oxygen),  and  easily  destroys 
the  organic  coloring-matters  of  which  the  pigment  of  the  wool 
consists.  It  is  necessary  to  neutralize  the  caustic  soda  in  the 
solution  by  the  addition  of  sulphuric  acid,  as  the  presence  of 
the  caustic  alkali  in  the  bleaching  bath  would  rapidly  destroy  the 
wool  fibre.  On  this  account  the  bath  is  usually  prepared  by 
first  adding  the  requisite  amount  of  sulphuric  acid  to  the  water, 
and  then  slowly  adding  the  sodium  peroxide.  Under  these 
circumstances  the  peroxide  reacts  with  the  sulphuric  acid  to  form 
sodium  sulphate  (glaubersalt)  and  hydrogen  peroxide: 

Na2O2+  H2SO4=  Na2SO4+  H2O2. 

In  order  to  insure' the  fact  that  there  is  no  free  caustic  soda  in  the 
solution  it  is  best  to  use  a  slight  excess  of  acid,  which  may  be 
indicated  by  testing  the  bath  with  a  piece  of  blue  litmus  paper. 
This  will  be  turned  red  in  the  presence  of  an  excess  of  acid.  The 
bleaching  effect  of  the  dissolved  hydrogen  peroxide,  however,  is 
stronger  in  an  alkaline  solution  than  in  an  acid  one;  this  is  due  to 
the  fact  that  the  peroxide  more  readily  decomposes  in  the  former 
solution.  Therefore  where  the  bleaching  bath  is  in  actual  use 
it  should  be  made  slightly  alkaline  with  a  reagent  which  will  not 
be  injurious  to  the  wool.  Sodium  silicate  has  been  found  to  be 
most  suitable  for  this  purpose,  though  ammonia  or  borax  may 
also  be  used.  In  this  connection  it  must  be  remarked  that  a 
large  excess  of  sulphuric  acid  must  be  avoided,  otherwise  when 
the  silicate  is  added  it  may  separate  in  a  jelly-like  mass  and  ruin 
the  bath.  During  the  bleaching  of  the  wool  the  bath  should  be 
maintained  at  a  temperature  of  about  100°  F.  If  the  temperature 
is  much  higher  than  this  the  hydrogen  peroxide  will  be  too  rapidly 
decomposed  and  loss  of  oxygen  will  be  occasioned;  if  the  bath  is 
too  strongly  alkaline  a  similar  condition  will  result. 


36  DYEING   AND    TEXTILE   CHEMISTRY. 

The  sodium  peroxide  bleaching  bath  must  be  contained  in  a 
wooden  vat  and  the  pipes  used  for  connections  and  heating 
should  be  of  lead.  The  presence  of  all  other  metals,  especially 
iron,  should  be  rigidly  excluded;  even  the  sulphuric  acid  and  the 
water  employed  in  the  bath  should  be  perfectly  free  from  iron, 
otherwise  very  inferior  results  will  be  obtained.  A  suitable 
strength  for  the  bleaching  bath  is  5  Ibs.  5  ozs.  of  sulphuric 
acid  (168°  Tw.)  and  4  Ibs.  of  sodium  peroxide  (98  per  cent.) 
per  100  gallons  of  water.  The  character  of  the  wool  or  the 
nature  of  the  material  to  be  bleached  may  necessitate  a  some- 
what stronger  bath  than  this,  in  which  case  the  same  relative 
proportions  of  acid  and  peroxide  should  be  used. 

Wool  bleached  with  sodium  peroxide  does  not  exhibit  the  same 
defects  as  noted  under  the  bleaching  with  sulphurous  acid.  It 
does  not  retain  any  substance  deleterious  to  dyed  colors,  nor  does 
the  yellow  tint  of  the  natural  pigment  return  on  exposure  to  the 
air,  for  this  pigment  appears  to  be  permanently  destroyed  by  the 
peroxide.  Attention  may  here  be  drawn  to  the  radical  difference 
in  the  principle  of  bleaching  with  sulphurous  acid  and  with  sodium 
peroxide.  In  the  former  case  the  bleaching  takes  place  through 
the  reducing  action  of  the  sulphur  dioxide,  whereas  in  the  latter 
case  the  bleaching  is  brought  about  by  the  strong  oxidizing 
action  of  the  peroxide. 

In  order  to  ascertain  if  the  bleaching  bath  of  sodium  peroxide 
after  use  still  contains  active  oxygen  for  further  use  in  bleaching 
the  following  test  may  be  carried  out:  A  small  quantity  of  the 
residual  liquor  is  placed  in  a  test-tube  and  a  few  drops  of  a  dilute 
solution  of  potassium  permanganate  are  added.  If  the  bath  still 
possesses  an  oxidizing  action,  the  violet  color  of  the  permanganate 
solution  will  be  destroyed. 

4.  Bleaching  Wool  with  Potassium  Permanganate.  —  This 
compound  is  also  a  strong  oxidizing  agent,  and  its  solution  will 
rapidly  destroy  the  natural  pigment  of  wool.  In  the  decompo- 
sition of  the  permanganate,  however,  whereby  it  liberates  oxygen, 
there  is  also  formed  an  insoluble  hydrated  oxide  of  manganese, 
which  is  precipitated  in  the  wool  and  imparts  to  it  a  brown  color. 


BLEACHING  OF   WOOL.  37 

The  decomposition  (or  oxidizing  action)  of  the  permanganate  is 
facilitated  by  the  presence  of  sulphuric  acid,  and  the  bleaching 
effect  is  completed  in  a  relatively  short  space  of  time.  In  order 
to  remove  the  insoluble  brown  compound  of  manganese  from  the 
fibre  it  is  best  to  treat  the  material  in  a  cold  dilute  solution  of 
sodium  bisulphite.  The  sulphurous  acid  present  in  the  latter 
solution  reacts  with  the  manganese  compound  to  form  a  colorless 
soluble  product,  and  the  fibre  is  left  in  a  clear  white  condition. 
Care  must  be  taken  in  this  connection  not  to  employ  an  excess  of 
sodium  bisulphite  solution,  otherwise  sulphurous  acid  will  be 
left  in  the  wool,  and  will  exhibit  the  defect  already  noted  under 
the  consideration  of  the  sulphurous  acid  bleach.  If  this  latter 
defect  is  avoided,  the  permanganate  bleach  on  wool  is  probably 
as  satisfactory  as  the  peroxide  bleach.  It  can  also  be  carried 
out  in  much  less  time.  Too  strong  a  solution  of  permanganate 
must  be  avoided,  otherwise  the  wool  will  acquire  a  harsh  feel,  due 
to  the  oxidation  of  the  fibre. 

With  regard  to  the  comparative  cost  of  the  several  methods  of 
bleaching  wool,  it  may  be  stated,  in  general,  that  the  sulphurous 
acid  bleach  is  the  cheapest,  while  the  peroxide  method  is  the 
dearest.  An  approximation  to  the  cost  of  the  three  methods 
(for  yarn)  is  as  follows: 

Sulphur  bleach  (gas) i  J  cts.  per  Ib. 

Permanganate  bleach 2  J  cts.  per  Ib. 

Peroxide  bleach 4j  cts.  per  Ib. 

The  permanganate  method  has  not  come  into  favor  as  yet, 
apparently  on  account  of  its  being  more  difficult  to  regulate. 

SAMPLES. 

40.  Woolen  yarn  before  bleaching  for  comparison. 

41.  Woolen  yarn  bleached  by  tinting  process. 

42.  Cotton  yarn  before  bleaching  for  comparison. 

43.  Cotton  yarn  bleached  by  tinting  process. 

44-  Woolen  yarn  bleached  with  sulphurous  acid  gas. 

45-  Woolen  yarn  bleached  with  sodium  bisulphite. 

46.  Sodium  bisulphite  bleach  treated  with  permanganate. 


38  DYEING   AND    TEXTILE   CHEMISTRY. 

47.  Effect  of  sulphurous  acid  in  yarn  on  dyed  colors. 

48.  Effect  on  dyed  colors  after  removing  sulphurous  acid. 

49.  Woolen  yarn  bleached  with  sodium  peroxide. 

50.  Woolen  yarn  treated  with  potassium  permanganate. 

51.  Woolen  yarn  bleached  with  permanganate  and  bisulphite. 

QUIZ  3. 

58.  What  is  the  natural  color  of  ordinary  wool?     Explain  the  theory  of 
bleaching  by  means  of  the  tinting  process.     What  coloring-matters  are  em- 
ployed, and  how  is  the  operation  conducted? 

59.  How  may  the  bleaching  action  of  sulphurous  acid  on  organic  coloring- 
matters  be  explained  ? 

60.  Give  the  process  of  bleaching  wool  with  sulphurous  acid  gas.     What 
length  of  time  is  required  ?     Why  is  it  necessary  to  tint  the  bleached  material  ? 
What  is  meant  by  "stoving"? 

61.  What  is  sodium  bisulphite  ?     What  is  its  active  bleaching  principle  ? 

62.  Give  the  complete  process  of  bleaching  wool  with  solutions  of  sodium 
bisulphite. 

63.  Explain  the  use  of  the  bath  of  sulphuric  acid  in  bleaching  with  sodium 
bisulphite. 

64.  What  disadvantages  are  attached  to  the  sulphurous  acid  method  of 
bleaching  wool  ?    How  could  you  test  the  bleached  wool  to  show  if  it  contained 
sulphurous  acid  ? 

65.  How  may  the  sulphurous  acid  left  in  the  wool  after  bleaching  be  removed 
or  neutralized  ? 

66.  What  defect  is  liable  to  arise  when  yarn  bleached  with  sulphurous  acid 
is  woven  with  dyed  yarns  ? 

67.  What  difference,  if  any,  did  you  notice  in  the  samples  prepared  from 
the  treated  and  untreated  bleached  skeins  when  plaited  with  a  dyed  yarn  ? 

68.  What  is  the  active  bleaching  principle  in  peroxides  ?    What  is  hydrogen 
peroxide  ?     How  is  it  made  ?    Why  is  it  not  much  used  directly  for  bleaching 
purposes  ? 

69.  What  is  sodium  peroxide?    How  is  it  made?    What  precautions  must 
be  taken  in  handling  and  using  it  ? 

70.  What  reaction  takes  place  when  sodium  peroxide  is  dissolved  in  water? 
What  reaction  takes  place  when  it  is  dissolved  in  dilute  sulphuric  acid  ? 

71.  Give  the  method  of  preparing  the  bleaching  bath  with  sodium  peroxide. 
Why  should  the  bath  still  be  slightly  acid  after  the  peroxide  is  added  ? 

72.  What  is  the  purpose  of  making  the  peroxide  bleaching  bath  slightly 
alkaline  before  bleaching,  and  what  alkalies  may  be  employed  fcr  the  purpose  ? 

73-   At  what  temperature  is  the  bath  maintained  in  bleaching  with  sodium 
peroxide  ?    What  length  of  time  is  required  for  the  bleaching  ? 


BLEACHING   OF   WOOL.  39 

74.  Describe  a  test  which  will  indicate  whether  the  peroxide  bath  is 
exhausted  or  not.  If  the  peroxide  bath  is  to  be  kept  over  how  is  it  best  pre- 
served ?  In  what  kind  of  a  vat  should  the  peroxide  bleaching  bath  be  used  ? 
How  is  the  bath  heated  ? 

75-  How  does  the  quality  of  the  peroxide  bleach  on  wool  compare  with  that 
with  sulphurous  acid  in  regard  to  cost,  permanency,  and  action  of  dyed  colors 
woven  with  the  bleached  yarn  ? 

76.  What  is  the  effect  of  traces  of  iron  in  the  peroxide  bleaching  bath  ?     Do 
other  metals  have  the  same  effect?    Why  should  all  the  chemicals  employed 
in  the  bath  be  perfectly  free  from  iron  ? 

77.  What   is   potassium   permanganate?      What   is    its   active    bleaching 
principle  ? 

78.  How  is  the  permanganate  bleaching  bath  prepared?     Explain  the 
chemical  reaction  which  occurs  when  wool  is  worked  in  an  acidulated  solution 
of  potassium  permanganate. 

79.  What  is  the  appearance  of  the  wool  after  coming  from  the  perman- 
ganate bath  ?    To  what  is  this  due  ? 

80.  What    after-treatment    is    necessary    in    the    permanganate    bleach? 
Explain  the  chemical  reaction  which  takes  place. 

81.  At  what  temperature  is  the  bleaching  with  potassium  permanganate 
conducted?    What  time  is  required  for  the  bleaching?    How  does  the  result 
compare  with  the  other  methods  of  bleaching  ? 


SECTION  IV. 
BLEACHING  OF  COTTON. 

Experiment  22.   Bleaching  Cotton  with  Chloride  of  Lime. : — 

Take  a  weighed  skein  of  cotton  yarn  and  boil  it  out  in  caustic 
soda  as  described  in  Exp.  12.  Take  another  weighed  skein 
and  boil  it  out  with  soap  as  described  in  Exp.  14;  also  a  third 
weighed  skein  scoured  with  Monopol  Soap  as  in  Exp.  15. 
Wash  these  skeins  well  and  steep  in  a  solution  of  chloride  of 
lime  (bleaching  powder)  of  2°  Tw.  strength.  Work  for  several 
minutes  until  the  fibre  is  thoroughly  saturated  with  the  liquor; 
then  immerse  in  the  solution  and  allow  to  stand  for  i  hour. 
Then  squeeze  and  rinse  in  water,  and  "sour"  by  passing  for 
15  minutes  through  a  cold  bath  of  sulphuric  acid  of  i°  Tw. 
strength.  Finally  wash  well  in  water  to  remove  all  trace  of 
acid.  Reweigh  each  skein  (52,  53,  54)  and  calculate  the  per- 
centage of  loss  in  each  case,  and  compare  the  bleach  obtained 
with  each  method  of  boiling-out.  Test  the  skeins  for  acid  by 
moistening  a  portion  with  a  little  water  and  pressing  against 
it  a  piece  of  blue  litmus  paper;  if  the  test  paper  turns  red, 
acid  is  still  present  in  the  fibre,  and  the  washing  has  been  imper- 
fect, with  a  result  that  the  cotton  will  soon  become  tender.  To 
test  the  bleached  cotton  for  traces  of  chlorine  which  may  remain 
after  bleaching,  take  a  portion  of  the  skein  and  warm  with  a 
small  amount  of  potassium  iodide-starch  solution;  if  a  blue  color 
is  developed,  there  is  still  chlorine  in  the  fibre.  The  test  solution 
may  be  prepared  by  dissolving  a  little  starch  paste  (made  by 
boiling  up  some  starch  with  water  to  a  paste)  in  a  solution  of 
potassium  iodide. 

Experiment  23.  Use  of  "  Anti-chlor  "  for  Removing  Chlorine 
in  Bleaching.  —  Take  a  skein  of  cotton  yarn  which  has  been 
boiled  out  in  caustic  soda  in  the  usual  manner,  and  bleach  it  for 

40 


BLEACHING  OF  COTTON.  41 

i  hour  in  a  cold  solution  of  chloride  of  lime  at  2°  Tw.,  then  wash 
in  water.  On  a  portion  of  the  skein  place  a  drop  or  two  of  the 
potassium  iodide-starch  solution,  and  it  will  be  found  that  a  blue 
color  is  developed,  showing  the  presence  of  chlorine.  Now  pass 
the  skein  through  a  bath  containing  a  little  sulphuric  acid  for  a 
few  minutes,  and  wash  again.  Test  with  the  potassium  iodide- 
starch  solution  again,  and  it  will  still  be  found  that  free  chlorine 
is  present.  Prepare  a  bath  containing  300  cc.  of  water  and 
i  gram  of  sodium  thiosulphate  (sodium  hyposulphite)  and  pass 
the  skein  through  this  solution  cold  for  10  minutes.  Wash  (55) 
and  again  test  with  the  potassium  iodide-starch  solution,  when 
it  will  be  found  that  the  free  chlorine  has  been  neutralized.  The 
sodium  hyposulphite  is  called  "anti-chlor"  when  used  for  this 
purpose;  sodium  bisulphite  will  also  answer  the  same  purpose. 

Experiment  24.  Bleaching  Loose  Cotton  for  Absorbent  Pur- 
poses. —  Weigh  out  10  grams  of  loose  cotton  (56)  and  boil  for 
i  hour  in  a  bath  containing  300  cc.  of  water  and  5  grams  of 
caustic  soda.  Rinse  off  well  in  fresh  water  and  bleach  in  a  cold 
solution  of  chloride  of  lime  at  2°  Tw.  for  i  hour.  Rinse,  and 
pass  through  a  cold  solution  of  sulphuric  acid  at  i°  Tw.  for  20 
minutes.  Then  wash  well  in  several  changes  of  water  until  all 
acid  is  removed.  Then  squeeze  and  dry  (57).  Reweigh  the 
sample  and  calculate  the  percentage  of  loss.  Test  the  bleached 
cotton  for  absorbent  qualities  by  placing  a  small  bit  of  it  on  the 
surface  of  cold  water;  if  it  is  perfectly  absorbent,  it  should  sink 
at  once.  Try  a  small  piece  of  raw  cotton  in  the  same  manner, 
and  it  will  be  found  that  the  latter  does  not  sink  at  all. 

Experiment  25.  Tinting  and  Softening  of  Bleached  Cotton.  -7* 
Boil  out  four  skeins  of  cotton  yarn  in  caustic  soda  in  the  usual 
manner;  wash  well  in  water,  and  bleach  for  i  hour  in  a  cold  bath 
of  chloride  of  lime  at  2°  Tw.  Wash,  squeeze,  and  pass  for 
15  minutes  through  a  cold  bath  of  sulphuric  acid  at  i°  Tw. 
Wash  in  two  changes  of  water.  Then  test  the  skeins  with  litmus 
paper,  and  the  chances  are  that  they  will  still  show  the  presence 
of  acid.  Set  one  of  the  skeins  aside  for  comparison  (58).  Take 
another  one  of  the  skeins  and  work  for  15  minutes  in  a  bath 


42  DYEING  AND    TEXTILE  CHEMISTRY. 


containing  300  cc.  of  water,  i  gram  of  soap,  and  -5%-$  per  cent. 
of  Methyl  Violet  5  B;  have  the  temperature  at  about  140°  F. 
Then  squeeze  and  dry  (59).  Take  a  third  skein  and  treat  in  the 
same  soap  bath,  but  add  T^  per  cent,  of  the  coloring-matter; 
squeeze  and  dry  (60).  Take  the  fourth  skein  and  treat  in  the 
same  manner  with  the  soap  solution,  but  add  yV  per  cent,  of  the 
dyestuff  ;  squeeze  and  dry  (61).  The  percentages  of  the  dyestuff 
are  to  be  calculated  on  the  weight  of  the  cotton  tinted.  That  is, 
7Jff  per  cent,  on  10  grams  of  cotton  would  be  0.0005  gram.  The 
solutions  provided  should  contain  o.i  gram  of  dyestuff  per  litre 
(1000  cc.)  ;  hence  i  cc.  would  represent  o.oooi  gram  of  dyestuff,  and 
it  would  require  5  cc.  to  give  the  necessary  vfo  per  cent.,  or  10  cc. 
for  Tta  per  cent.,  or  20  cc.  for  A  per  cent.  After  the  several 
skeins  have  dried,  compare  the  feel  or  softness  of  the  first  with 
that  of  the  others  which  have  been  treated  with  the  soap  bath. 
Also  compare  the  degrees  of  tinting  of  the  latter  three  skeins  and 
the  difference  in  the  character  of  the  white  obtained  in  each  case. 

Experiment  26.  Use  of  Acetic  Acid  in  Bleaching.  —  Boil  out  a 
skein  of  cotton  yarn  with  caustic  soda  in  the  usual  manner  and 
bleach  for  i  hour  in  a  cold  solution  of  chloride  of  lime  at  2°  Tw. 
containing  also  a  little  acetic  acid.  Then  wash  well  in  fresh 
water  and  pass  through  the  dilute  soap  bath  as  described  above 
(62).  It  will  be  noticed  that  some  chlorine  is  given  off  in  the 
bleach  bath  containing  the  acetic  acid,  but  the  bleaching  does  not 
require  the  after  use  of  an  acid,  from  which  there  is  always 
danger  of  tendering  the  fibre. 

Experiment  27.  Use  of  Lime  Boil  in  Bleaching  Cotton.  — 
Prepare  a  solution  of  lime-water  by  slaking  10  grams  of  quick- 
lime (oxide  of  calcium,  CaO)  with  a  small  quantity  of  water,  and 
then  diluting  to  300  cc.  Boil  a  weighed  skein  of  cotton  yarn  in 
this  bath  for  i  hour,  then  wash  and  pass  through  a  cold  bath 
containing  300  cc.  of  water  and  3  cc.  of  concentrated  hydrochloric 
acid;  work  for  15  minutes.  Wash  and  bleach  for  i  hour  in  a 
cold  solution  of  chloride  of  lime  at  2°  Tw.  Wash,  and  pass  back 
through  the  cold  acid  bath  for  15  minutes.  Then  wash  well  and 
soap  as  usual  in  a  dilute  warm  soap  bath.  Wash  and  dry  (63). 


BLEACHING  OF  COTTON.  43 

Reweigh  and  calculate  the  percentage  of  loss.  Compare  this 
method  of  bleaching  with  the  previous  ones.  The  first  treatment 
with  acid  is  required  in  order  to  dissolve  out  any  lime  compounds 
formed  in  the  fibre,  which  would  otherwise  remain  and  tender 
the  cotton,  and  also  not  allow  the  chloride  of  lime  to  act  as  per- 
fectly as  it  should. 

Experiment  28.  Use  of  Sodium  Hypochlorite.  —  Prepare  a  bath 
containing  sodium  hypochlorite  solution  of  i°  Tw.  In  this  cold 
bath  steep  for  i  hour  a  skein  of  cotton  yarn  previously  boiled  out 
with  caustic  soda.  Wash  and  pass  through  a  cold  bath  of  sul- 
phuric acid  at  i°  Tw.  for  15  minutes.  Then  wash  well  and  soap 
as  usual  (64).  Sodium  hypochlorite  is  prepared  by  adding  a 
solution  of  soda  ash  to  one  of  chloride  of  lime,  allowing  the 
precipitate  of  calcium  carbonate  to  settle  and  drawing  off  the 
clear  liquor.  It  is  more  efficient  as  a  bleaching  agent  than 
chloride  of  lime,  and  is  also  less  liable  to  cause  tendering  of  the 
fibre.  It  is  more  expensive,  however,  than  chloride  of  lime. 

Experiment  29.  Comparison  of  the  Use  of  Sulphuric  and  Hydro- 
chloric Acids  in  Bleaching  Cotton.  —  Take  two  skeins  of  cotton 
yarn  which  have  been  boiled  out  with  caustic  soda  and  bleach 
them  in  the  usual  manner  with  chloride  of  lime  solution  at  2°  Tw. 
Without  washing,  take  one  of  the  skeins  and  pass  through  a 
bath  containing  300  cc.  of  water  and  3  cc.  of  hydrochloric  acid 
cold  for  15  minutes,  then  wash  well  and  dry  (65).  Take  the 
other  skeins  and  treat  in  a  similar  manner  with  a  solution  of  2  cc. 
of  sulphuric  acid  in  300  cc.  of  water;  wash  well  and  dry  (66). 
Notice  that  in  the  bath  containing  the  hydrochloric  acid  there 
is  no  precipitate  formed,  as  the  lime  compound  with  this  acid  is 
soluble  in  water;  whereas  in  the  sulphuric  acid  bath  a  precipitate 
of  calcium  sulphate  is  formed  which  will  remain  to  a  greater  or 
lesser  extent  in  the  cotton. 

Experiment  30.  Use  of  Chlorozone.  —  Prepare  a  bath  contain- 
ing 300  cc.  of  water  and  20  cc.  of  "chlorozone,"  and  bleach  a 
skein  of  cotton  yarn  which  has  been  boiled  out  in  caustic  soda  in 
this  bath  for  i  hour.  Enter  the  skein  at  a  temperature  of  about 
200°  F.  and  allow  to  cool  in  the  bath  without  further  heating. 


44  DYEING  AND   TEXTILE  CHEMISTRY. 

Then  squeeze,  and  pass  through  a  bath  of  sulphuric  acid  solution 
at  i°  Tw.  cold  for  15  minutes.     Wash  well  and  dry  (67). 

NOTES. 

i.  General  Method  of  Cotton  Bleaching.  —  Ordinary  American 
cotton  is  of  a  comparatively  white  color  when  in  the  natural  raw 
state;  but,  nevertheless,  it  contains  a  small  amount  of  natural 
pigment  matter  of  a  yellowish  brown  color.  This  pigment 
is  so  small  in  amount  that  it  does  not  interfere  in  the  general 
dyeing  of  cotton;  but  when  light,  delicate  shades  are  desired  in 
dyeing,  or  when  the  cotton  material  is  to  be  left  in  the  white 
condition  for  sale,  it  is  usually  necessary  to  bleach  it.  Cotton 
in  the  loose  state  is  very  seldom  bleached,  since  the  bleaching 
processes  considerably  deteriorate  the  spinning  qualities  of  the 
fibre  by  removing  its  waxy  coating;  the  fibre  is  also  made  more 
brittle  by  the  bleaching  which  causes  a  largely  increased  amount 
of  waste  in  carding  and  spinning;  furthermore,  after  bleached 
cotton  is  passed  through  the  numerous  mechanical  operations  of 
carding  and  spinning  it  will  become  more  or  less  discolored  and 
will  have  acquired  considerable  dirt,  so  that  the  final  yarn  or 
cloth  would  be  unsatisfactory  as  a  bleached  product.  Yarn  is 
sometimes  spun  from  bleached  stock  for  the  manufacture  of  knit 
goods,  thus  giving  a  half -bleached  product;  it  is  also  used  for  half- 
bleached  filling  yarns.  Cotton  yarn  is  frequently  bleached  both 
for  the  purpose  of  being  dyed  in  delicate  shades  and  of  being  man- 
ufactured into  white  goods  —  more  especially  knitted  fabrics,  lace, 
etc.  The  chief  form,  however,  in  which  cotton  is  bleached  is  that 
of  cloth ;  in  which  case  it  may  be  used  (a)  as  a  bleached  bottom  for 
the  dyeing  of  delicate  shades  or  for  colors  such  as  Turkey-red, 

(b)  for  print  cloth  in  the  many  processes  of  calico-printing,  and 

(c)  for  the  purpose  of  being  sold  in  the  white  state,  or  as  a  market- 
bleach. 

Though  a  number  of  chemical  agents  have  been  suggested  for 
the  bleaching  of  cotton,  the  one  which  has  been  most  successfully 
and  extensively  employed  is  chloride  of  lime  or  bleaching  powder. 
The  effective  bleaching  agent  in  the  chloride  of  lime  is  chlorine 


BLEACHING  OP   COTTON.  45 

in  a  loosely  combined  condition.  But  the  chlorine  itself  does 
not  accomplish  the  bleaching  in  a  direct  manner.  In  the  process 
the  chlorine  is  liberated  in  the  nascent  condition  in  the  pres- 
ence of  water;  the  latter  is  decomposed  by  the  chlorine  yielding 
hydrochloric  acid  and  nascent  oxgyen,  and  it  is  this  oxygen 
which  causes  the  bleaching  action.  The  chemical  reactions  may 
be  thus  represented : 

Chloride  of  lime  — >  chlorine. 
Chlorine  +  water  — >  hydrochloric  acid  +  oxygen. 

Chlorine  of  itself  is  without  any  bleaching  action,  a  fact  which 
has  been  demonstrated  by  allowing  dry  chlorine  to  act  on  sensitive 
colors,  the  result  being  that  the  colors  were  not  destroyed. 

2.  The   Operations   in   Cotton    Bleaching.  —  There   are   five 
distinct  operations  in  the  proper  bleaching  of  cotton : 

(1)  Boiling-out;  this  is  really  a  scouring  operation,  the  object 
of  which  is  to  remove  all  the  waxy  and  resinous  matters  in  the 
fibre. 

(2)  Treatment  with  bleaching  powder  solution;  this  is  for  the 
purpose  of  destroying  the  natural  coloring-matter  in  the  fibre, 
and  also  for  the  breaking  down  of  various  non-cellulosic  matters 
associated  with  the  cellulose  of  the  cotton. 

(3)  Treatment  with  a  dilute  solution  of  acid;  this  is  generally 
termed  "  souring,"  and  is  for  the  purpose  of  dissolving  the  lime 
compounds  in  the  fibre  left  from  the  bleaching  powder  and  to 
decompose    any   chlorine   compounds   which    may    have   been 
formed. 

(4)  Washing;  this  is  for  the  purpose  of  removing  all  soluble 
matters  resulting  from  the  action  of  the  bleaching  powder  and 
the  acid ;  also  for  the  removal  of  the  acid  from  the  fibre. 

(5)  Soaping  and  tinting;  this  is  for  the  purpose  of  neutralizing 
the  last  traces  of  acid,  and  also  for  softening  the  cotton.     The 
tinting  is  to  give  a  slight  bluish  tone  to  the  white. 

3.  Boiling-out.  —  The  scouring  of  cotton  intended  for  bleach- 
ing must  be  carried  out  much  more  thoroughly  than  when  the 
operation  is  merely  for  the  purpose  of  wetting-out  the  cotton 


46  DYEING   AND    TEXTILE   CHEMISTRY. 

previous  to  dyeing.  In  the  latter  case  it  is  only  necessary  that 
the  external  waxy  coating  on  the  fibre  be  removed  or  softened  in 
order  that  water  may  easily  impregnate  the  cotton.  But  in 
boiling-out  for  bleaching  it  is  required  to  remove  very  com- 
pletely all  the  impurities  in  the  fibre,  including  the  waxy  coating, 
the  miscellaneous  resinous  matters,  the  albuminous  substances, 
and  in  fact  all  matters  of  a  non-cellulosic  character.  It  is  the 
object  in  bleaching  to  obtain  a  practically  pure  cellulose  for  the 
bleached  cotton.  For  the  wetting-out  of  cotton,  a  dilute  solution 
of  soap,  soda  ash,  or  soluble  oil  only  is  required,  but  for  the  proper 
boiling-out  of  the  cotton  a  rather  strong  solution  of  caustic  alkali 
or  soda  ash  is  required;  the  time  of  boiling  is  much  prolonged 
(usually  7  to  10  hours),  and  it  is  generally  conducted  under 
pressure  in  a  closed  kier.  This  very  thorough  boiling-out  of  the 
cotton  previous  to  bleaching  is  necessitated  by  the  fact  that  if  any 
resinous  matters  (or  so-called  pectin)  are  left  in  the  fibre,  the 
bleached  material  will  gradually  become  yellow  on  exposure  to 
light  and  air.  Formerly  lime  was  very  generally  used  for  the 
boiling-out  of  cotton,  in  which  case  it  was  necessary  to  pass  the 
material  through  an  acid  bath  (so-called  gray  sour)  to  remove 
particles  of  lime  which  might  otherwise  "burn"  the  fibre.  It 
was  thought  that  boiling  with  lime  caused  a  more  perfect  decom- 
position and  removal  of  the  resinous  substances  in  the  cotton. 
Lime,  however,  is  not  so  much  used  at  the  present  time,  it  being 
replaced  by  caustic  soda,  the  action  of  which  is  more  efficient 
and  requires  less  time.  When  the  lime  boil  is  used  (chiefly  with 
piece-goods)  a  previous  boiling  with  resin  soap  is  usually  given. 
Silicate  of  soda  is  a  very  good  alkali  for  boiling-out  cotton  for 
bleaching.  Many  popular  "bleach  assistants"  consist  of  varying 
proportions  of  silicate  of  soda,  soda  ash,  and  caustic  soda.  Silicate 
of  soda  does  not  give  the  cotton  such  a  harsh  feel  as  when  caustic 
soda  is  used. 

4.  Bleaching  Powder  and  its  Use.  —  Bleaching  powder  or 
chloride  of  lime  is  prepared  by  treating  slaked  lime  with  chlo- 
rine gas.  Its  chemical  formula  is  Cai  ,  or  CaOCl2.  It  is 


BLEACHING  OF  COTTON.  47 

commonly  known  as  "chemic"  or  " bleach."  Chloride  of  lime 
is  a  yellowish  white  powder  which  smells  strongly  of  chlorine, 
especially  if  moistened.  When  treated  with  water  it  partly  goes 
into  solution  and  partly  forms  a  bulky  white  precipitate  consist- 
ing for  the  most  part  of  lime  (CaO) .  The  solution  has  a  yellowish 
color  and  is  the  liquid  employed  for  the  preparation  of  the  bleach- 
ing bath.  A  good  quality  of  chloride  of  lime  should  contain 
about  36  per  cent,  of  available  chlorine,  that  is  to  say,  chlorine 
which  is  active  in  the  bleaching  process.  The  exact  chemical 
reactions  which  take  place  in  the  use  of  chloride  of  lime  are  not 
thoroughly  understood,  though  they  have  been  the  subject  of 
much  investigation.  •  It  is  probable  that  when  chloride  df  lime  is 
dissolved  in  water,  calcium  chloride  (CaCl2),  hypochlorous  acid 
(HC1O),  and  calcium  oxide  (CaO)  are  formed,  as  follows: 

2  CaOCl2+  H2O  =  CaGL^  2  HC1O  +  CaO. 

Hence  the  bleaching  liquor,  as  used,  may  be  considered  as  a  solu- 
tion of  hypochlorous  acid ;  the  calcium  chloride  produces  no  effect 
in  bleaching.  No  doubt  a  portion  of  the  lime  also  remains  in 
solution  as  calcium  hypochlorite  (Ca(OCl)2).  The  insoluble  cal- 
cium oxide  is  filtered  off  (or  settled  out)  before  the  bleaching 
liquor  is  used.  Hypochlorous  acid  is  a  very  unstable  substance 
(especially  in  the  presence  of  organic  matter,  such  as  the  fibres), 
and  it  readily  decomposes  into  water  and  an  oxide  of  chlorine 
(CljO),  as  follows: 

2  HC10  -»  H20  +  C120. 

The  latter  is  a  strong  oxidant,  as  it  splits  up  into  chlorine  and 
free  oxygen:  C12O^C12+  O. 

The  chlorine  thus  liberated  reacts  with  the  water  present  to  form 
hydrochloric  acid  and  another  portion  of  free  oxygen: 

Cl2-h  H20  =  2HC1  +  O. 

Under  certain  conditions  it  is  probable  that  the  hypochlorous 
acid  decomposes  directly  into  hydrochloric  acid  and  oxygen: 

HC10  -*  HC1  +  O. 


48  DYEING   AND    TEXTILE   CHEMISTRY. 

Solutions  of  bleaching  powder  are  best  prepared  by  first 
grinding  the  powder  with  a  small  quantity  of  cold  water  until  a 
thin  uniform  paste  is  obtained,  and  then  diluting  with  cold  water 
and  allowing  to  settle  until  the  liquor  is  clear.  A  concentrated 
solution  of  bleaching  powder  will  show  a  density  of  about  18°  Tw. 
For  the  preparation  of  the  bleaching  bath  this  is  diluted  to  about 
2°  Tw.  Care  should  be  taken  that  no  undissolved  particles  of 
bleaching  powder  pass  into  the  bleaching  bath,  otherwise  the 
cotton  may  become  tendered  in  spots.  It  is  also  necessary  that 
the  material  be  completely  immersed  in  the  solution  during  the 
bleaching,  for  under  the  influence  of  the  oxygen  of  the  air  the 
bleaching  liquor  will  seriously  weaken  the  cotton.  The  tem- 
perature of  the  bleaching  bath  should  always  be  cold;  it  is  only 
in  exceptional  cases  where  low  grade  material  is  treated  that  the 
bleaching  liquor  is  ever  warmed,  and  even  then  only  to  about 
100°  F.  The  time  of  immersion  of  the  cotton  in  the  bleaching 
solution  should  be  from  one-half  to  one  hour;  too  long  a  treat- 
ment will  cause  a  tendering  of  the  fibre. 

5.  The  Acid  Treatment.  —  When  the  cotton  comes  from  the 
solution  of  bleaching  powder  it  contains  a  considerable  amount 
of  lime  compounds,  partly  as  calcium  hypochlorite  and  partly 
as  calcium  oxide;  there  is  also  present  calcium  chloride.  The 
acid  treatment  (generally  known  as  "souring")  is  for  the  purpose 
of  decomposing  the  calcium  hypochlorite  and  the  calcium  oxide : 

Ca(OCl)2  +  H2S04  =  CaS04  +  2  HC1O. 
CaO  +  H2SO4  =  CaSO4  +  H2O. 

In  the  first  case  hypochlorous  acid  is  formed  which  furthers 
and  completes  the  bleaching.  In  both  cases  calcium  sulphate 
(gypsum)  is  formed  as  a  white,  finely  divided,  though  insoluble, 
powder.  This  is  quite  easily  removed  from  the  fibre  by  subse- 
quent washing,  and  being  of  a  very  neutral  character,  has  no 
action  on  the  cotton.  As  a  rule,  the  cotton  comes  up  much 
whiter  after  the  souring,  and  the  evolution  of  free  chlorine  gas  is 
very  evident.  The  souring  is  usually  done  in  a  cold  bath  of 
sulphuric  acid  of  i°  Tw.  density.  Stronger  solutions  are  not 


BLEACHING  OF  COTTON.  49 

advisable,  as  they  are  liable  to  weaken  the  cotton.  Hydrochloric 
acid  may  be  used  to  replace  the  sulphuric,  in  which  case  calcium 
chloride  will  be  formed,  which  is  a  very  soluble  salt  and  is  more 
easily  removed  from  the  fibre  than  the  insoluble  calcium  sulphate. 
To  obtain  an  equivalent  acid  strength  about  2.25  parts  by  weight 
of  hydrochloric  acid  should  be  used  for  i  part  by  weight  of 
sulphuric  acid.  In  case  the  boiling-out,  bleaching,  etc.,  are 
carried  out  in  machines  containing  copper  or  bronze  a  small 
amount  of  copper  salt  will  be  formed  which  with  sulphuric  acid 
will  produce  an  insoluble  precipitate  of  a  double  sulphate  of 
copper  and  calcium.  This  will  become  fixed  in  the  cotton  and 
is  very  difficult  to  remove.  If  hydrochloric  acid,  however,  is  used, 
no  insoluble  precipitate  will  be  formed,  and  the  copper  salt  is 
easily  washed  away. 

6.  Washing.  —  Immediately  following  the  souring  the  cotton 
should  be  thoroughly  washed  with  fresh  water  in  order  to  remove 
as  far  as  possible  all  of  the  acid.     Should  the  washing  be  delayed 
for  any  length  of  time  there  is  danger  of  portions  of  the  bleached 
material  becoming  dry,  which  will  cause  tender  spots  to  form. 
The  washing  should  be  continued  until  the  presence  of  acid  is  no 
longer  evident;  this  may  be  shown  by  testing  the  cotton  with  a 
piece  of  blue  litmus  paper,  which  will  turn  red  if  any  acid  is 
present.     The  washing  is  also  for  the  purpose  of  removing  the 
sulphate  of  calcium  which  is  precipitated  in  the  cotton  during  the 
souring.     The  chlorine  which  is  generated  in  the  material  during 
the  same  process  is  also  removed  by  the  washing,  and  care  should 
be  taken  to  eliminate  it  very  thoroughly,  otherwise  the  cotton  will 
subsequently  be  weakened  by  over-oxidation  and  the  formation 
of  acid  in  the  fibre.     The  presence  of  chlorine  in  the  cotton 
may  be  tested  for  by  a  mixed  solution  of  potassium  iodide  and 
starch  paste,  which  will  give  a  blue  color  with  a  trace  of  chloride. 
This  test  depends  on  the   fact  that  chlorine  liberates  iodine 
from  potassium  iodide,  and  the  free  iodine  combines  with  the 
starch  to  form  a  compound  with  an  intensely  blue  color. 

7.  Soaping  and  Tinting.  —  The  final  operation  essential  to  the 
bleaching  of  cotton  is  that  of  soaping.     For  this  purpose  the 


50  DYEING  AND    TEXTILE  CHEMISTRY. 

material  is  treated  in  a  dilute  lukewarm  solution  of  soap.  The 
latter  should  be  of  good  quality  and  free  from  any  ingredients 
liable  to  cause  discolorations  in  the  dried  and  finished  bleach. 
The  object  of  the  soaping  is  primarily  to  soften  the  cotton,  which 
will  have  acquired  considerable  harshness  in  the  boiling-out, 
bleaching,  and  acid  treatments.  It  also  has  the  purpose  of 
neutralizing  absolutely  all  trace  of  acid  in  the  cotton,  and  thus 
preventing  subsequent  tendering.  In  the  soap  bath  it  is  also 
customary  to  add  a  small  quantity  of  a  blue  dyestuff,  such  as 
Cotton  Blue,  Methylene  Blue,  Soluble  Prussian  Blue  (bleacher's 
tint),  etc.,  for  the  purpose  of  tinting  the  bleached  white  to  a  satis- 
factory bluish  tone.  In  case  a  cream-white  bleach  is  desired,  the 
tinting  is  omitted.  Care  must  be  had  not  to  tint  the  cotton  too 
strongly,  otherwise  the  material  will  appear  dull  and  dirty. 

In  the  entire  process  of  bleaching,  the  cotton  will  lose  in  weight 
about  5  to  7  per  cent.  If  properly  bleached  the  loss  in  tensile 
strength  should  not  be  over  5  per  cent.  The  elasticity  will  be 
somewhat  less  than  that  of  the  unbleached  cotton.  The  tendering 
of  cotton  in  bleaching  may  be  due  to  several  causes: 

(1)  Oxidation  caused  by  exposure  to  the  air  during  the  boiling- 
out  process.     If  a  skein  of  cotton  yarn  is  so  hung  as  to  be  partly 
suspended  in  a  solution  of  caustic  soda  and  boiled  thus  for  some 
time,  it  will  be  found  to  be  seriously  weakened  at  that  part  where 
it  comes  into  contact  simultaneously  with  the  alkaline  liquor 
and  the  air. 

(2)  Oxidation  due  to  the  use  of  too  strong  a  solution  of  bleach- 
ing powder,  or  to  its  becoming  overheated. 

(3)  The  drying  of  acid  in  the  fibre  or  of  particles  of  lime  from 
sediment  in  the  bleaching  bath. 

The  oxidation  of  cotton  leads  to  the  formation  of  a  substance 
known  as  oxy cellulose,  which  is  structureless  and  pliable  in 
character,  hence  its  formation  leads  to  a  weakening  of  the  fibre. 
The  presence  of  oxycellulose  may  usually  be  recognized  by 
staining  the  cotton  with  a  dilute  solution  of  Methylene  Blue; 
ordinary  cotton  has  but  slight  affinity  for  this  coloring-matter, 
whereas  oxycellulose  is  strongly  dyed. 


BLEACHING  OF  COTTON.  51 

4 

8.  Use   of   "Anti-chlor."  —  As   the   perfect   removal   of   the 
chlorine  from  the  cotton  is  very  difficult  by  simply  washing  with 
water,  it  is  sometimes  expedient  to  neutralize  the  free  chlorine  with 
a  suitable  chemical  agent.     The  chief  substances  used  as  "  anti- 
chlors"  are  sodium  hyposulphite  (Na2S2O3)   and  sodium  bisul- 
phite (NaHSO3).     The  reactions  in  the  two  cases  are  as  follows: 

Na2S203+  4  C12+  5  H2O  =  Na,SO4+  H2SO4  +  8  HC1. 
2  NaHSO3+  2  C12+  2  H2O  =  Na2SO4  +  4  HC1  +  H2SO4. 

After  treatment  with  anti-chlor  the  bleached  cotton  should  be 
well  washed  and  soaped,  for  it  will  be  noticed  from  the  above 
reactions  that  acid  is  formed  in  both  cases. 

9.  Bleaching  Loose  Cotton.  —  Loose  cotton  is  seldom  bleached 
for  purposes  of   spinning,   as  the   bleaching  operation  consid- 
erably deteriorates  the  spinning  qualities  of   the  fibre.      This 
is  due  to  the  fact  that  in  the  bleaching  the  waxy  matters  are 
removed,  and  hence  the  fibre  becomes  less  plastic  and  coherent, 
besides  being  more  brittle.     Sometimes,  however,  cotton  in  the 
half-spun  condition  is  bleached,  and  there  are  mechanical  devices 
available  for  the  proper  bleaching  of  cotton  roving  and  stubbing. 
A  cold  method  for  bleaching  loose  cotton  has  been  proposed 
wherein  the  cotton  is  first  treated  in  a  suitable  machine  so  that 
cold  water  is  forced  through  the  mass  under  considerable  pressure; 
then  a  cold  solution  of  bleaching  powder  is  circulated  through 
the  cotton,  and  subsequently  dilute  acid,  followed  by  a  thorough 
washing  and  soaping.     This  method  is  said  to  leave  the  cotton 
almost  unimpaired  as  to  its  spinning  qualities.     Such  a  process  is 
attaining  considerable  practical  value  for  the  spinning  of  filling 
cops  from  bleached  stock. 

Loose  cotton,  however,  is  largely  bleached  for  use  as  medicinal 
absorbent  cotton.  The  object  in  view  in  this  case  is  not  only  to 
obtain  a  white  and  pure  fibre,  but  also  to  make  it  highly  absorbent 
of  liquids.  In  fact,  the  purpose  is  not  so  much  to  bleach  the 
cotton  in  the  sense  of  destroying  the  color,  as  to  remove  all 
impurities  from  the  fibre  which  may  in  any  manner  interfere  with 
its  ready  absorption  of  liquids.  Hence,  the  chief  operation  is  a 


52  DYEING   AND    TEXTILE   CHEMISTRY. 

very  thorough  boiling-out  to  remove  perfectly  the  waxy  and 
resinous  matters.  For  this  purpose  the  cotton  is  boiled  in  a  com- 
paratively strong  solution  of  caustic  soda  under  pressure  for  8  to 
10  hours.  After  this  treatment  it  is  bleached  in  the  usual  manner 
with  chloride  of  lime  and  sulphuric  acid.  The  quality  of  absorb- 
ent cotton  is  tested  by  the  readiness  with  which  it  sinks  in  water. 

10.  Bleaching  with  Acetic  Acid.  —  In  some  cases  cotton  is 
bleached   with   the   use   of  acetic   rather  than   sulphuric   acid. 
Acetic  acid  is  less  liable  to  cause  tendering  of  the  fibre,  and  the 
acid  may  be  added  directly  to  the  bath  of  chloride  of  lime,  though 
this  causes  a  considerable  loss  of  chlorine.     Otherwise  the  acetic 
acid  acts  in  the  same  manner  as  sulphuric  acid.     Although  this 
method  has  been  strongly  advocated  by  some  chemists  it  does  not 
seem  to  have  acquired  much  practical  importance. 

11.  Bleaching  with  Sodium  Hypochlorite.  —  This  reagent  is 
also  known  as  "chloride  of  soda,"  and  corresponds  to  chloride  of 
lime  in  its  bleaching  properties.     It  may  conveniently  be  pre- 
pared by  adding  a  solution  of  soda  ash  to  one  of  chloride  of  lime 
until  no  further  precipitation  takes  place.     The  white  sediment 
of  calcium  carbonate  is  allowed  to  settle  and  the  clear  liquor 
containing  sodium  hypochlorite  in  solution  is  drawn  off  and  used 
for  bleaching.     It  is  sometimes  used  for  the  bleaching  of  fine 
and  delicate  fabrics  and  where  it  is  not  desirable  to  introduce  any 
lime  into  the  cotton. 

A  bleaching  agent  similar  to  sodium  hypochlorite  is  prepared 
by  saturating  a  cold  solution  of  caustic  soda  with  chlorine  gas. 
This  solution  is  prepared  under  a  variety  of  names  such  as 
chlorozone,  oxychlorine,  etc.  It  usually  has  a  pink  color, 
due  to  the  presence  of  certain  impurities  in  the  caustic  soda 
farming  colored  salts  with  the  chlorine.  It  is  used  in  the  same 
manner  as  sodium  hypochlorite  and  is  a  very  efficient  bleaching 
agent.  Solutions  of  sodium  hypochlorite  prepared  electrolytically 
by  the  action  of  the  electric  current  on  a  solution  of  common 
salt  are  also  employed  in  bleaching.  It  is  claimed  that  liquors 
thus  prepared  show  a  much  higher  bleaching  efficiency  than 
ordinary  solutions  of  sodium  hypochlorite. 


BLEACHING  OF  COTTON. 


53 


SAMPLES. 

52.  Cotton  yarn  boiled-out  with  caustic  soda  and  bleached. 

53.  Cotton  yarn  boiled-out  with  soap  and  bleached. 

54-  Cotton  yarn  boiled-out  with  Monopol  Soap  and  bleached. 

55.  Bleached  yarn  treated  with  anti-chlor! 

56.  Loose  cotton  in  raw  state. 

57.  Loose  cotton  bleached  and  absorbent. 

58.  Bleached  yarn  untinted. 

59.  Tinted  with  ?fa  per  cent,  of  dyestuff. 

60.  Tinted  with  T^TF  per  cent,  of  dyestuff. 

61.  Tinted  with  ^  per  cent,  of  dyestuff. 

62 .  Cotton  yarn  bleached  with  use  of  acetic  acid. 

63.  Cotton  yarn  boiled -out  with  lime  and  bleached. 

64.  Cotton  yarn  bleached  with  sodium  hypochlorite. 

65.  Bleaching  with  use  of  hydrochloric  acid. 

66.  Bleaching  with  use  of  sulphuric  acid. 

67.  Cotton  yarn  bleached  with  chlorozone. 

RECORD    OF    RESULTS. 


No.  Test. 

Weight  before 
Bleaching. 

Weight  after 
Bleaching. 

Loss  in 
Weight. 

Percentage  of 
Loss. 

22(&) 

22(b)  

22(C)  

24. 

27  .  . 

QUIZ  4. 

82.  What  is  the  natural  color  of  raw  cotton?     For  what  purposes  is  it 
necessary  to  bleach  cotton?      In  which  form,  loose  stock,  yarn,  or  cloth,  is 
cotton  mostly  bleached  ? 

83.  What  bleaching  agent  is  principally  used  in  connection  with  cotton? 
Explain  the  principle  of  its  bleaching  action. 

84.  What  are  the  several  operations  necessary  in  the  bleaching  of  cotton? 
Explain  the  function  of  each  process. 

85.  Why  must  the  boiling-out  of  cotton  before  bleaching  be  very  thorough? 
What  materials  are  removed  in  the  boiling-out  process? 


54  DYEING   AND    TEXTILE   CHEMISTRY. 

86.  What  is  chloride  of  lime?     Under  what  other  names  is  it  known  in 
bleaching  ? 

87.  Explain  the  various  chemical  reactions  taking   place  when  bleaching 
with  chloride  of  lime. 

88.  What  reaction  occurs  when  chloride  of  lime  is  dissolved  in  water? 
How  are  bleaching  powder  solutions  prepared  ? 

89.  At  what  density  is  the  solution  of  chloride  of  lime  usually  employed  for 
bleaching  purposes?    Why  should  the  cotton  be  completely  immersed  in  the 
liquor? 

90.  For  what  length  of  time  is  the  cotton  steeped  in  the  bleaching  powder 
solution  and  at  what  temperature  ? 

91.  Is  the  decolorization  of  the  cotton  complete  after  steeping  in  the  chemic 
solution  ?    What  after-treatment  is  necessary  ? 

92.  What  is  meant  by  a  "sour"?    How  is  the  souring  done ?    Explain  the 
reaction  of  sulphuric  acid  on  chloride  of  lime. 

93.  The  acid  solution  employed  for  souring  is  used  at  what  strength  ?    The 
odor  of  what  gas  is  noticed  when  the  cotton  is  soured  ? 

94.  Why  is  it  necessary  to  wash  the  cotton  very  thoroughly  after  souring? 
How  would  you  test  for  the  presence  of  acid  in  the  bleached  cotton  ?    For  the 
presence  of  chlorine  ? 

95.  How  is  the  test  solution  for  detecting  chlorine  prepared?     Explain  the 
reaction  which  takes  place  in  this  test. 

96.  How  much  does  cotton  yarn  lose  in  weight  by  bleaching?     If  properly 
bleached  does  cotton  yarn  lose  much  in  tensile  strength  ? 

97.  Give  the  different  causes  which  may  lead  to  the  tendering  of  cotton  in 
the  operations  of  bleaching.     What  is  oxycellulose,  and  how  may  its  presence 
in  bleached  cotton  be  detected  ? 

98.  What  is  meant  by  an  "anti-chlor,"  and  for  what  purpose  is  it  employed 
in  bleaching  ?    What  anti-chlors  are  chiefly  used  ?     Explain  the  chemistry  of 
their  action. 

99.  For  what  purpose  is  loose  cotton  chiefly  bleached?     How  is  the  bleach- 
ing carried  out  ?    What  is  the  difference  in  the  behavior  towards  cold  water  of 
loose  raw  cotton  and  loose  bleached  cotton  ? 

100.  How  is  bleached  cotton  tinted  ?    About  how  much  dyestuff  is  required 
for  proper  tinting? 

101.  What  is  the  purpose  of  "softening"  bleached  cotton,  and  how  is  this 
done? 

1 02.  In  what  manner  may  cotton  be  bleached  with  the  use  of  acetic  acid? 
Explain  the  chemistry  of  this  process. 

103.  How  is  cotton  boiled-out  with  lime?    What  treatment  is  necessary 
after  the  boiling-out,  and  why  ?    Why  has  the  lime  boil  been  recommended  ? 

104.  What  is  sodium  hypochlorite ?    How  is  it  prepared?     How  is   it 
employed  for  the  bleaching  of  cotton  ? 


BLEACHING  OF  COTTON.  55 

105.  How  does  sodium  hypochlorite  compare  with  chloride  of  lime  as  a 
bleaching  agent  ? 

1 06.  What  difference  is  to  be  noticed  in  the  use  of  sulphuric  and  hydro- 
chloric acids  in  the  bleaching  of  cotton?     Give  the  chemical  reactions  which 
take  place  in  both  cases. 

107.  What  are  chlorozone  and  oxy chlorine?    How  are  these  prepared? 
How  are  they  employed  in  bleaching? 


SECTION  V. 
CLASSIFICATION  OF  DYES. 

Experiment  31.  Action  of  Acid  Dyes.  —  Prepare  a  bath  con- 
taining 300  cc.  of  water  and  5  cc.  of  Formyl  Violet  solution.  Take 
a  scoured  test-skein  of  woolen  yarn,  wet  it  out  with  warm  water, 
and  place  it  in  the  above  bath;  boil  for  one-half  hour;  then  wash 
well  in  fresh  water  and  dry  (68).  Repeat  this  test,  using  a  bath 
containing  300  cc.  of  water,  5  cc.  of  Formyl  Violet  solution,  and 
10  cc.  of  sulphuric  acid  solution.  It  will  be  found  that  in  the 
first  test  the  wool  is  only  slightly  dyed,  whereas  in  the  second 
test  it  is  well  dyed  (69).  Repeat  the  second  test,  using  a  wet-out 
test-skein  of  cotton  yarn;  wash  well  and  dry  (70).  It  will  be 
found  that  the  cotton  is  only  slightly  tinted  by  the  acid  dyestuff. 
Repeat  the  test  again,  using  a  skein  of  boiled-off  silk,  and  it  will 
be  found  that  the  silk  (71)  is  dyed  like  the  wool. 

Experiment  32.  Action  of  Basic  Dyes.  —  Prepare  a  bath 
containing  300  cc.  of  water  and  10  cc.  of  Magenta  solution, 
and  boil  a  test-skein  of  woolen  yarn  therein  for  one-half  hour, 
then  wash  well  and  dry  (72).  It  will  be  noticed  that  the  dyestuff 
is  taken  up  by  the  wool  directly.  Repeat  the  test,  using  a  skein  of 
silk.  It  will  be  found  that  the  silk  (73)  also  dyes  directly  with 
the  basic  coloring-matter.  Repeat  the  test  again,  using  a  skein  of 
cotton  yarn.  It  will  be  found  that  in  this  case  the  cotton  (74)  is 
only  slightly  tinted  with  the  dyestuff.  Take  a  second  skein  of 
cotton  and  work  it  for  one-half  hour  in  a  bath  containing  300  cc. 
of  water  and  10  cc.  of  tannic  acid  solution  at  180°  F.  Squeeze, 
and  then  dye  as  before  described  in  a  fresh  bath.  It  will  now  be 
found  that  the  treated  cotton  (75)  will  combine  with  the  basic 
dyestuff. 

Experiment  33.  Action  of  Substantive  Dyes.  —  Prepare  a 
dye-bath  containing  300  cc.  of  water  and  10  cc.  of  a  solution  of 

56 


CLASSIFICATION   OF  DYES.  57 

Benzopurpurin  46,  and  boil  a  test-skein  of  wool  therein  for 
one-half  hour,  then  wash  well  and  dry  (76).  It  will  be 
noticed  that  the  wool  combines  directly  with  the  substantive 
dyestuff. 

Repeat  the  test,  using  a  skein  of  silk,  and  it  will  be  found  that 
the  silk  will  also  be  dyed  (77).  Repeat  the  test  again,  using 
a  skein  of  cotton  yarn;  the  cotton  will  also  be  dyed  (78). 

Experiment  34.  Action  of  Mordant  Dyes.  —  Dye  a  skein  of 
woolen  yarn  in  a  bath  containing  300  cc.  of  water  and  10  cc.  of 
Alizarin  Red;  boil  for  one-half  hour.  It  is  found  that  the  dyestuff 
is  not  taken  up  to  any  extent  by  the  fibre  (79).  Boil  a  second 
skein  of  woolen  yarn  in  a  bath  containing  10  cc.  of  chrome 
solution  (potassium  bichromate)  for  one-half  hour;  then  rinse 
and  dye  as  above  given  (80).  The  dyestuff  will  now  be  absorbed 
by  the  mordanted  wool,  combining  with  the  chromium  oxide  in 
the  fibre  to  form  a  color-lake.  Dye  a  skein  of  cotton  yarn  with 
Alizarin  Red  in  the  above  manner;  it  will  be  found  that  the  fibre 
has  no  attraction  for  the  dyestuff  (81).  Mordant  a  second  skein 
of  cotton  yarn  by  working  in  a  cold  solution  containing  200  cc. 
of  water  and  5  grams  of  ferric  chloride  for  10  minutes;  squeeze 
and  pass  through  a  cold  solution  containing  200  cc.  of  water 
and  2  grams  of  soda  ash.  This  furnishes  a  deposit  of  iron  oxide 
on  the  fibre  and  gives  the  latter  a  buff  color  (82).  Now  dye 
this  mordanted  skein  in  the  above  manner  with  Alizarin  Red,  and 
it  will  be  found  that  the  dyestuff  is  absorbed  and  the  cotton 
becomes  dyed  (83).  Dye  a  skein  of  silk  with  the  solution  of 
Alizarin  Red;  it  will  be  noticed  that  silk  is  similar  to  wool  and 
Cotton,  and  is  not  dyed  (84)  by  the  alizarin  dye.  Mordant  a 
second  skein  of  silk  with  chrome  in  the  same  manner  as  was  used 
for  wool,  and  then  dye  with  the  Alizarin  Red.  It  will  be  found 
that  the  mordanted  silk  (85),  like  the  wool,  will  combine  with  the 
dyestuff. 

Experiment  35.  Action  of  Pigment  Dyes.  —  Work  a  skein  of 
cotton  yarn  for  15  minutes  in  a  cold  solution  containing  200  cc. 
of  water  and  5  grams  of  lead  acetate.  Squeeze  and  then  work  for 
15  minutes  in  a  second  cold  solution  containing  200  cc.  of  water 


58  DYEING  AND    TEXTILE  CHEMISTRY. 

and  2  grams  of  potassium  bichromate.  Wash  well  and  dry 
(86).  A  yellow  pigment  consisting  of  chrome  yellow  (chromate 
of  lead)  will  be  formed  in  the  fibre  through  the  chemical  reaction 
between  the  lead  acetate  and  the  potassium  bichromate.  This 
pigment  is  purely  of  mineral  nature  and  is  simply  deposited  in  the 
cells  of  the  fibres  and  does  not  combine  with  the  substance  of  the 
fibre  itself,  as  is  the  case  with  the  other  methods  of  dyeing. 

NOTES. 

i.  General  Classification  of  Dyestuffs.  —  With  respect  to 
their  general  properties  nearly  all  coloring-matters  may  be 
divided  into  four  general  classes,  as  follows: 

(a)  Acid  Dyes.  (c)  Substantive  Dyes. 

(b)  Basic  Dyes.          (d)  Mordant  Dyes. 

This  classification  in  a  general  way  is  based  on  the  chemical 
nature  of  the  dyestuff  and  its  reaction  towards  the  fibre.  The 
following  is  a  brief  summary  of  these  properties: 

(a)  Acid  Dyes.     Salts  of  color-acids;  dye  animal  fibres  directly;  do  not  dye 
vegetable  fibres;  mostly  applied  to  wool  and  silk. 

(b)  Basic  Dyes.     Salts  of  color-bases;  dye  animal  fibres  directly;  dye  vege- 
table fibres  on  a  tannin  mordant;  mostly  applied  to  cotton  and  silk. 

(c)  Substantive  Dyes.     Of  neutral  chemical  nature;  dye  both  animal  and 
vegetable  fibres  directly;  mostly  applied  to  cotton  and  somewhat  to  both  wool 
and  silk. 

(d)  Mordant  Dyes.     Of  neutral  chemical  nature;  dye  neither  animal  nor 
vegetable  fibres  directly,  but  require  a  metallic  mordant;  mostly  applied  to 
wool. 

The  great  majority  of  the  dyestuffs  used  at  the  present  time 
are  derived  from  coal  tar,  the  vegetable  dyes,  with  few  exceptions, 
being  almost  obsolete. 

(a)  Acid  Dyes.    Mostly  derived  from  azo  compounds  of  benzene. 
(6)  Basic  Dyes.    Mostly  derived  from  aniline. 

(c)  Substantive  Dyes.    Mostly  derived  from  benzidine. 

(d)  Mordant  Dyes.    Mostly  derived  from  anthracene. 


CLASSIFICATION  OF  DYES.  59 

Previous  to  the  discovery  of  the  coal-tar  dyes,  the  coloring- 
matters  employed  were  of  either  vegetable  or  mineral  origin. 

(a)  Vegetable  Dyes.     Logwood,  fustic,  hypernic,  cochineal,  madder,  cutch, 
camwood,  etc. 

(b)  Mineral  Dyes.     Iron  black,  iron  buff,  manganese  bistre,  chrome  yellow, 
etc. 

The  first  coal-tar  dyestuff  was  discovered  in  1856  by  Per  kin; 
it  was  known  as  Mauve,  and  was  soon  followed  by  other  aniline 
dyes.  It  is  wrong,  however,  to  apply  the  term  " aniline"  colors  to 
all  coal-tar  dyes,  as  there  are  now  many  which  are  not  derived 
from  aniline. 

For  the  same  amount  of  coloring-matter  the  coal-tar  dyes 
are  much  cheaper  than  the  vegetable  colors;  they  have  also 
far  greater  intensity  of  color,  are  much  brighter,  and  in  general  are 
faster. 

Based  on  their  general  methods  of  application,  we  may  classify 
practically  all  of  the  dyes  used  at  the  present  time  into  the  follow- 
ing groups : 

(a)  Acid  dyes,  such  as  Acid  Violet,  Naphthol  Yellow,  etc. 

(b)  Basic  dyes,  such  as  Magenta,  Methylene  Blue,  etc. 

(c)  Mordant  dyes,  such  as  Alizarin  Red,  Gallocyanine,  etc. 

(d)  After-chromed  dyes,  such  as  Chromotrop,  Diamond  Black, 
etc. 

(e)  Substantive  dyes,  such  as  Benzopurpurin,  Chrysophenine, 
etc. 

'(/)  Developed  dyes,  such  as  Diamine  Black  BH,  Primuline,  etc. 

(g)  Naphthol  dyes,  such  as  Paranitraniline  Red,  etc. 

(h)  Coupled  dyes,  such  as  Benzo  Nitrol  Brown,  etc. 

(i)  Sulphur  dyes,  such  as  Immedial  Black,  Katigen  Green,  etc. 

(/)    Vat  dyes,  such  as  Indigo,  Indanthrene  Blue,  etc. 

(k)  Oxidized  dyes,  such  as  Aniline  Black. 

(/)  Mineral  pigment  dyes,  such  as  Chrome  Yellow,  Prussian 
Blue,  etc. 

The  most  important  of  these  classes,  and  those  containing  the 
greatest  number  and  the  most  diversified  colors,  are  the  four 
groups  mentioned  in  the  first  paragraph  of  this  section. 


60  DYEING  AND    TEXTILE  CHEMISTRY. 

The  acid  dyes  are  principally  used  for  the  dyeing  of  wool  and 
silk,  and  only  to  a  limited  extent  for  the  dyeing  of  cotton  or  other 
vegetable  fibres.  They  are  applied  to  the  animal  fibres  in  baths 
containing  either  sulphuric  acid  or  acetic  acid.  The  basic  dyes 
are  used  chiefly  for  the  dyeing  of  cotton  and  silk;  only  a  few 
members  of  this  group  are  used  in  wool-dyeing.  They  are 
applied  to  the  animal  fibres  directly  from  neutral  baths.  For 
cotton,  or  other  vegetable  fibres,  a  mordant  of  an  acid  character 
(such  as  tannic  acid)  is  required.  The  mordant  dyes  are  almost 
exclusively  used  for  the  dyeing  of  wool,  with  the  exception  of 
Alizarin  Red,  which  is  also  largely  used  for  the  dyeing  of  cotton 
(for  Turkey-red).  These  dyes  do  not  have  a  direct  affinity  for 
any  of  the  fibres,  and  require  the  use  of  a  metallic  mordant 
(usually  potassium  bichromate)  in  their  application.  The  after- 
chromed  dyes  are  very  similar  to  the  mordant  dyes  in  their  general 
characteristics,  but  the  mordant  is  applied  after  the  dyeing. 
These  colors  are  used  exclusively  on  wool  and  have  a  direct 
affinity  for  this  fibre,  though  the  color  so  obtained,  as  a  rule,  has 
little  value.  The  after-chroming  process  usually  alters  this  color 
considerably  and  gives  it  fastness.  The  substantive  dyes  are 
so  called  because  they  have  a  direct  affinity  for  all  fibres.  They 
are  primarily  cotton  dyes,  though  they  are  also  used  to  some 
extent  on  wool  and  silk.  They  are  applied  in  neutral  baths. 
The  developed  dyes  are  used  almost  exclusively  on  cotton,  though 
a  few  are  also  applicable  to  silk.  They  are  first  dyed  in  a  manner 
similar  to  the  substantive  colors  in  a  neutral  solution;  the  dyed 
material  is  then  treated  with  a  solution  of  nitrous  acid  (obtained 
by  the  addition  of  acid  to  a  solution  of  sodium  nitrite),  —  a 
process  known  as  diazotizing, — and  afterwards  with  a  solution  of 
beta-naphthol  (or  other  similar  body),  which  is  known  as  the 
developer,  and  from  which  this  class  of  dyes  receives  its  name. 
By  these  operations  a  new  dyestuff  is  built  up  in  the  fibre.  The 
naphthol  dyes  are  somewhat  similar  in  general  to  the  preceding 
group,  only  the  order  of  the  operations  is  reversed.  The  material 
to  be  dyed  is  first  treated  with  a  solution  of  beta-naphthol  (or 
other  similar  developer),  and  then  with  a  solution  of  a  diazotized 


CLASSIFICATION  OF  DYES.  6 1 

base  representing  the  dyestuff.  In  this  manner  a  dyestuff  is 
actually  made  in  the  fibre.  These  dyes  are  but  few  in  number 
and  are  applied  only  to  cotton.  The  coupled  dyes  are  another 
similar  group,  the  material  being  first  dyed  with  a  substantive  color 
and  then  treated  with  a  solution  of  diazotized  paranitraniline ;  this 
resulting  in  the  formation  of  a  new  dyestuff  in  the  fibre.  Such 
dyes  are  applicable  only  to  cotton  and  are  quite  limited  in  number 
and  range  of  color.  The  sulphur  dyes  are  also  applied  almost 
exclusively  to  cotton,  though  in  certain  cases  they  may  also  be 
used  on  silk.  They  are  dyed  with  the  aid  of  sodium  sulphide 
which  is  added  to  the  dye-bath,  and  the  dyestuff  apparently  con- 
tains sulphur  compounds  in  its  composition.  In  other  respects 
they  are  very  similar  to  the  substantive  dyes.  The  vat  dyes  form 
a  small  group  of  colors  employed  on  all  the  fibres.  The  dyestuffs 
themselves  are  insoluble  and  require  to  be  first  reduced  by  means 
of  a  strong  reducing  agent  (such  as  sodium  hydrosulphite  or 
other  suitable  substance)  and  dissolved  in  an  alkaline  liquor. 
This  combination  forms  the  so-called  "vat."  Indigo  is  the  chief 
representative  of  this  group,  though  other  dyes  of  a  similar 
character  have  lately  been  added,  such  as  the  indanthrene,  dian- 
threne,  and  algol  colors,  as  well  as  the  thio-indigo  colors.  The 
group  of  oxidized  dyes  is  practically  limited  to  only  one  member 
known  as  Aniline  Black.  This  dye,  which  is  extensively  used,  is 
formed  by  the  proper  oxidation  of  aniline  directly  in  the  fibre. 
It  is  used  principally  on  cotton  and  to  a  lesser  extent  on  silk. 
The  mineral  pigment  dyes  are  colored  compounds  of  the  metals 
formed  by  the  precipitation  in  the  fibre  of  suitable  metallic  salts, 
such  as  chrome  yellow  formed  by  precipitation  of  lead  acetate  in 
the  fibre  with  potassium  bichromate.  These  dyes  are  almost 
entirely  used  for  dyeing  cotton;  some  were  formerly  used  for 
dyeing  wool  and  silk,  but  this  application  of  them  is  now  almost 
entirely  discontinued. 

2.  General  Theory  of  Dyeing.  —  There  have  been  two  main 
theories  to  explain  the  general  process  of  dyeing.  The  chemical 
theory  supposes  that  dyeing  involves  a  chemical  reaction  between 
the  fibre  and  the  dyestuff  and  that  a  definite  chemical  compound 


62  DYEING  AND    TEXTILE   CHEMISTRY. 

known  as  the  color-lake  is  thus  produced.  The  mechanical 
theory,  on  the  other  hand,  considers  the  effect  of  dyeing  to  be 
simply  a  deposit  of  colored  particles  in  the  substance  of  the  fibre, 
and  the  combination  so  formed  to  be  merely  a  mechanical  mix- 
ture. The  chemical  theory  is  supported  by  the  facts  that  the 
.animal  fibres  (wool  and  silk)  exhibit  well-defined  chemical 
reactivities  of  an  acid  and  a  basic  character,  and  that  these  fibres 
readily  dye  with  the  acid  and  basic  dyestuffs;  whereas  cotton,  which 
is  practically  inert  as  far  as  chemical  reactivity  is  concerned, 
shows  no  pronounced  attraction  for  these  dyes;  but  if  an  acid 
mordant  is  added  to  the  cotton  fibre  then  the  latter  exhibits  the 
power  of  combining  with  basic  dyes,  or  if  a  basic  mordant  (a 
metallic  oxide)  is  added  the  cotton  will  be  able  to  combine  with 
the  acid  dyes.  Furthermore,  in  the  case  of  mordant  dyes,  the 
combination  between  the  dyestuff  and  the  mordant  may  be  made 
independent  of  the  fibre,  and  a  chemical  reaction  undoubtedly 
takes  place  in  the  formation  of  such  a  color-lake.  On  the  other 
hand,  it  may  be  shown  that  the  substantive  colors  dye  cotton 
quite  readily  without  any  evidence  of  a  chemical  reaction.  Also 
almost  any  porous  substance  (even  such  substances  as  unglazed 
porcelain,  finely  divided  silica,  etc.)  will  take  up  a  dyestuff  from 
solution  (especially  the  basic  dyes)  and  become  truly  dyed  thereby. 
Even  unmordanted  cotton  will  dye  with  many  of  the  acid  and 
basic  dyes  if  concentrated  solutions  are  employed,  and  the  colors 
so  obtained  have  a  certain  degree  of  fastness.  With  the  present 
knowledge  of  dyeing,  it  seems  more  reasonable  to  assume  that 
the  substance  of  the  fibres  is  capable  of  dissolving  such  bodies 
as  dyestuffs  and  mordants,  bringing  about  a  condition  which  we 
know  as  solid  solution,  which  merely  means  that  one  solid  sub- 
stance is  dissolved  in  another  solid.  According  to  this  view  of 
regarding  the  phenomena  of  dyeing,  the  dissolved  coloring- 
matter  in  its  water-solution  passes  into  a  fibre-solution.  There 
are  many  factors  influencing  the  degree  and  rapidity  of  this  form 
of  solution,  among  which  the  most  important  appear  to  be  the 
chemical  activity  existing  between  the  dyestuff  (or  mordant)  and 
the  fibre,  the  heating  of  the  dye-bath,  the  presence  of  various 


CLASSIFICATION  OF  DYES.  63 

chemicals  in  the  dye-bath  or  fibre,  and  the  mass-relations  between 
the  fibre,  the  dye-bath,  and  the  dyestuff. 

Though  we  cannot  regard  the  chemical  activity  of  the  fibre 
toward  the  dyestuff  as  primarily  the  cause  of  dyeing,  neverthe- 
less there  can  be  no  doubt  but  that  this  factor  often  exerts  a 
determining  influence  in  the  process.  This  is  especially  true 
when  we  consider  the  chemical  relations  between  the  acid 
and  basic  dyes  and  the  animal  fibres  wool  and  silk.  The 
chemical  combination  possible  between  the  fibre  and  the 
dyestuff  in  this  case  no  doubt  determines  the  fixation  of  the 
solution  of  the  coloring-matter  in  the  substance  of  the  material 
dyed. 

Heat  also  appears  to  play  an  important  role  in  dyeing  as  it 
does  in  all  forms  of  solution.  By  elevating  the  temperature  the 
mobility  of  the  molecular  aggregates  of  both  the  dyestuff  and 
the  fibre  is  increased  so  as  to  allow  of  a  more  intimate  mixture  of 
these  molecules  with  one  another.  The  rapidity  and  degree  of 
dyeing  is  nearly  always  greater  in  a  hot  dye-bath  than  in  a  cold 
one;  and  the  proper  regulation  of  this  temperature  permits  the 
dyer  to  so  regulate  the  taking-up  of  the  color  by  the  fibre  as  to 
obtain  even  and  well-penetrated  dyeings. 

The  presence  of  certain  chemicals  in  the  dye-bath  also  has  an 
important  influence  in  the  regulation  of  the  dyeing.  In  the  case 
of  acid  dyes,  the  presence  of  acid  (such  as  sulphuric  or  acetic) 
liberates  the  free  color-acid  from  the  dyestuff  salt  and  thus  pro- 
motes and  accelerates  the  dyeing  by  allowing  of  the  ready  and 
complete  combination  between  the  fibre-base  and  this  color-acid. 
We  may  represent  this  reaction  somewhat  in  the  following 
graphical  manner: 

color-acid  :  soda    +    H2SO4    =    color-acid  :  hydrogen 
dyestuff  salt       sulphuric  acid          free  color-acid 

+  Na2SO4 
sodium  sulphate 

Color-acid  +  wool-base  =  color-lake. 


64  DYEING   AND    TEXTILE   CHEMISTRY. 

The  basic  dyes  appear  to  become  dissociated  when  dissolved 
in  water;  that  is  to  say,  the  color-base  of  these  dyes  becomes 
spontaneously  separated  from  the  acid  with  which  it  is  combined 
in  the  form  of  its  dyestuff-salt ;  and  the  free  color-base  thus  formed 
combines  readily  with  the  acid  component  of  the  fibre  to  form  the 
color-lake.  Therefore  the  basic  dyes  can  be  applied  to  the  animal 
fibres  in  a  neutral  dye-bath.  As  a  rule,  however,  they  are  taken 
up  too  rapidly  by  the  fibre  to  allow  of  even  dyeing,  so  the  bath  is 
usually  made  slightly  acid  (with  acetic  acid)  in  order  to  retard 
the  dyeing  action. 

The  presence  of  glaubersalt  (or  other  neutral  salt  such  as 
common-salt)  appears  to  influence  the  dyeing  reaction  by  more 
perfectly  distributing  the  dyestuff  molecules  through  the  fibre 
substance.  This  is  more  especially  true  of  its  action  in  reference 
to  the  acid  and  basic  dyes.  It  may  be  said  to  impede  the  progress 
of  the  dyestuff  molecules  in  their  passage  from  the  water  solution 
to  that  of  the  fibre.  The  number  of  glaubersalt  molecules  is 
very  large  compared  with  the  number  of  those  of  the  dyestuff, 
and  hence  its  action  may  be  compared  to  that  of  a  large  crowd  of 
people  impeding  the  progress  of  a  man  in  walking  towards  a  defi- 
nite point.  The  action  of  common-salt  in  the  case  of  the  sub- 
stantive dyes  appears  to  assume  a  somewhat  different  character; 
it  reduces  the  solubility  of  the  dyestuff  in  the  liquid  of  the  dye- 
bath  and  hence  increases  its  relative  solubility  in  the  fibre,  and 
thus  helps  to  exhaust  the  bath  by  forcing  more  color  on  the  cotton. 
The  action  of  these  chemicals  appears  to  be  about  the  same 
if  they  are  contained  in  the  fibre  itself  rather  than  in  the  dye- 
bath.  If  wool,  for  example,  is  treated  with  sulphuric  acid, 
and  washed,  it  appears  to  retain  the  sulphuric  acid  possibly  in 
some  weak  form  of  combination.  If  such  wool  is  placed  in  a 
bath  containing  an  acid  dyestuff,  the  dyeing  reaction  will  proceed 
without  further  addition  of  acid. 

The  mass-relations  existing  between  the  fibre,  the  dye-bath, 
and  the  dyestuff  also  have  an  important  influence  in  the  dyeing 
reaction.  It  would  be  natural  to  expect  that  the  greater  the 
concentration  of  the  dye-bath,  that  is,  the  greater  the  mass  of  the 


CLASSIFICATION   OF  DYES.  6$ 

dyestuff  in  proportion  to  the  mass  of  the  water,  the  more  color  will 
be  taken  up  by  the  fibre.  The  same,  of  course,  is  true  when  the 
mass  of  the  fibre  is  greater  in  proportion  to  that  of  the  water. 

3.  The  Use  of  Mordants.  —  It  has  been  seen  that  certain  dyes 
(such  as  the  alizarin  and  anthracene  series)  do  not  form  stable 
combinations  with  the  fibres.  If  wool,  for  example,  is  boiled  in 
a  solution  of  Alizarin  Red,  in  a  certain  sense  it  will  become  dyed, 
but  the  color  may  easily  be  washed  from  the  fibre.  In  other 
words,  though  the  dyestuff  is  soluble  in  the  fibre,  the  color-lake 
does  not  become  "fixed."  These  dyes,  however,  form  very 
permanent  color-lakes  with  many  metallic  oxides,  such  as  those 
of  aluminium,  chromium,  iron,  etc.  Furthermore,  wool  (and  silk 
also)  has  the  property  of  dissolving  and  fixing  these  metallic  salts 
much  in  the  same  manner,  for  instance,  as  basic  dyes  are  taken 
up  by  the  fibre.  Therefore  if  the  animal  fibres  are  first  boiled  in 
a  solution  of  such  metallic  salt  a  certain  quantity  of  the  metallic 
oxide  becomes  dissolved  and  fixed  in  the  substance  of  the  wool 
(or  silk) ,  and  the  fibre  so  prepared  can  then  be  dyed  a  permanent 
color  with  the  alizarin  (or  other  mordant)  dyestuffs.  Cotton  (and 
the  vegetable  fibres  in  general)  does  not  have  the  property  of  dis- 
solving and  fixing  these  metallic  salts  (or  mordants)  to  any  extent; 
hence  this  method  of  mordanting  and  dyeing  is  not  applicable  to 
the  vegetable  fibres.  The  vegetable  fibres  do,  however,  possess 
the  property  of  combining  with  tannic  acid,  and  this  furnishes  a 
method  of  so  preparing  these  fibres  that  they  may  be  dyed  with 
the  basic  dyestuffs.  The  salts  of  those  metals  which  are  more 
or  less  easily  dissociated  in  boiling  water  are  most  applicable  as 
mordants  for  the  animal  fibres.  These  salts  include  compounds 
of  chromium,  aluminium,  iron,  tin,  copper,  etc.,  the  most 
important  mordants  for  wool  being  potassium  bichromate 
(chrome)  and  alum  (or  aluminium,  sulphate).  Pyrolignite  of 
iron  (crude  ferrous  acetate)  and  the  so-called  nitrate  of  iron 
(really  a  ferric  sulphate)  are  used  largely  for  silk;  although  their 
use  in  this  connection  is  primarily  for  purposes  of  weighting,  their 
mordanting  action  being  a  secondary  consideration.  The  color- 
lake  in  the  case  of  a  mordant  dye  consists  of  the  triple  compound : 


66  DYEING   AND    TEXTILE   CHEMISTRY. 

fibre  —  metallic  oxide  —  dyestuff.  The  mordant  dyes  are  of  a 
mild  acid  character  or  contain  groups  which  permit  of  them 
uniting  chemically  with  the  basic  metallic  oxide.  On  account  of 
the  fact  that  cotton  cannot  be  readily  mordanted  after  the  manner 
of  wool,  the  general  class  of  mordant  dyes  find  little  or  no  appli- 
cation to  this  fibre.  About  the  only  instance  of  their  use  in  this 
connection  is  the  dyeing  of  Turkey-red,  and  this  requires  a  special 
and  complicated  process.  One  feature  to  be  noticed  in  connec- 
tion with  the  mordant  dyes  is  that  the  same  dyestuff  often  gives 
very  different  colors  on  different  mordants;  Alizarin  Red,  for 
instance,  when  dyed  on  a  chrome  mordant  gives  a  rather  dull 
purplish  red;  on  an  aluminium  mordant  it  gives  a  bright  red;  on 
a  tin  mordant  it  gives  a  scarlet;  and  on  an  iron  mordant  it  gives 
a  dull  purple. 

4.  The  Pigment  Dyes. — These  coloring-matters  are  of  a  differ- 
ent nature  from  those  of  the  other  groups.  While  the  latter  are 
organic  compounds  and  mostly  derivatives  from  coal  tar,  the 
pigment  dyes  are  of  a  mineral  nature.  They  consist,  really, 
of  mineral  pigments  precipitated  more  or  less  mechanically  in 
the  fibre.  Chrome  yellow,  for  instance,  consists  of  lead  chromate, 
a  compound  of  an  intensely  yellow  color  which  may  be  prepared 
entirely  independent  of  the  fibre,  and  is  used  extensively  as  a 
pigment  for  the  preparation  of  paints. 

SAMPLES. 

68.  Wool  dyed  with  acid  dye  without  acid. 

69.  Wool  dyed  with  acid  dye  with  acid. 

70.  Cotton  dyed  with  acid  dye. 

71.  Silk  dyed  with  acid  dye. 

72.  Wool  dyed  with  basic  dye. 

73.  Silk  dyed  with  basic  dye. 

74.  Unmordanted  cotton  dyed  with  basic  dye. 

75.  Mordanted  cotton  dyed  with  basic  dye. 

76.  Wool  dyed  with  substantive  dye. 
77-  Silk  dyed  with  substantive  dye. 

78.  Cotton  dyed  with  substantive  dye. 

79.  Unmordanted  wool  dyed  with  mordant  dye. 

80.  Mordanted  wool  dyed  with  mordant  dye. 


CLASSIFICATION  OF  DYES.  67 

81.  Unmordanted  cotton  dyed  with  mordant  dye. 

82.  Cotton  mordanted  with  an  iron  salt. 

83.  Mordanted  cotton  dyed  with  mordant  dye. 

84.  Unmordanted  silk  dyed  with  mordant  dye. 

85.  Mordanted  silk  dyed  with  mordant  dye. 

86.  Cotton  dyed  with  pigment  dye. 

QUIZ  5. 

1 08.  Into  what  classes  are  dyestuffs  in  general  divided?    What  is  the 
difference  between  a  dyestuff  and  a  pigment  ? 

109.  From  what  substance  are  most  of  the  dyes  at  present  derived  ?    What 
kinds  of  dyes  were  employed  in  former  times? 

no.  When  and  by  whom  was  the  first  coal-tar  dyestuff  made?  Are  all 
coal-tar  dyes  "aniline"  dyes?  How  do  the  coal-tar  dyes  compare  with  the 
vegetable  dyes  in  cheapness,  intensity  of  color,  brightness,  and  general  fastness  ? 

in.  Give  an  outline  of  the  chemical  theory  of  dyeing.  What  facts  argue 
for  and  against  this  theory? 

112.  What  is  the  physical  theory  of  dyeing?     What  is  meant  by  a  "solid 
solution"? 

113.  What  is  the  chemical  constitution  of  an  acid  dyestuff?     Explain  why 
acid  dyes  combine  directly  with  the  animal  fibres  and  not  with  the  vegetable 
fibres. 

114.  Why  is  acid  added  to  the  dye-bath  in  dyeing  with  acid  dyes  ?     Explain 
the  chemical  reaction  which  takes  place  between  the  acid  and  the  dyestuff. 

115.  Which  acid  is  mostly  used  in  dyeing  acid  colors,  and  in  what  amount  ? 

1 1 6.  What  is  the  eventual  color-lake  obtained  in  dyeing  acid  colors  on 
wool  or  silk  ? 

117.  What  is  the  chemical  constitution  of  a  basic  dye?     Explain  the 
chemical  difference  between  a  basic  and  an  acid  dye. 

1 1 8.  Explain  why  the  animal  fibres  combine  directly  with  basic  dyes  while 
the  vegetable  fibres  do  not.     How  may  the  latter  be  so  treated  as  to  be  capable 
of  dyeing  with  the  basic  dyes  ? 

119.  Why  is  it  not  necessary  to  add  either  acid  or  alkali  to  the  dye-bath  in 
dyeing  basic  dyes?    What  is  meant  by  "dissociation"  ? 

120.  What  is  meant  by  the  term  "  substantive  dye  "  ?    How  does  this  class 
differ  from  the  acid  and  basic  dyes  chemically? 

121.  How  do  substantive  dyes  react  with  wool,  silk,  and  cotton?     Is  any 
addition  to  the  bath  necessary  in  dyeing  these  colors  ? 

122.  What  is  meant  by  a  mordant?     By  a  mordant  dye?    How  do  these 
dyes  react  with  animal  and  vegetable  fibres  ? 

123.  How  may  wool  and  silk  be  mordanted  in  order  to  dye  with  the  mor- 
dant dyes?     Can  cotton  be  also  mordanted  in  the  same  manner  as  wool? 
Why? 


68  DYEING  AND    TEXTILE  CHEMISTRY. 

124.  What  class  of  metallic  salts  are  employed  as  mordants?     Briefly 
explain  the  chemistry  of  the  mordanting  process. 

125.  Of  what  does  the  color-lake  consist  when  mordant  dyes  are  employed  ? 
Why  are  mordant  dyes  not  much  applied  to  cotton  ? 

126.  Does  Alizarin  Red  give  the  same  color  with  a  chrome  as  with  an  iron 
mordant  ?    What  is  the  color  in  each  case  ? 

127.  What  is  meant  by  a  pigment  dye?     How  are  these  dyes  obtained  in 
the  fibre? 

128.  Of  what  does  Chrome  yellow  consist?    How  does  it  differ  in  chemical 
nature  from  the  other  dyes  so  far  employed  ? 

129.  How  is  Chrome  yellow  applied  to  cotton  ?     Give  the  chemical  reactions 
which  occur  in  its  formation. 

130.  To  what  fibres  are  acid  dyes  mostly  applied?    Basic  dyes?    Mor- 
dant dyes  ?    Pigment  dyes  ?    Substantive  dyes  ? 


SECTION  VI. 
APPLICATION  OF  ACID  DYES. 

Experiment  36.  General  Method  of  Dyeing  Acid  Colors  on 
Wool.  —  Prepare  a  dye-bath  containing  300  cc.  of  water,  20  per 
cent,  of  glaubersalt,  4  per  cent,  of  sulphuric  acid,  and  i  per  cent, 
of  Acid  Magenta.  Have  the  temperature  of  the  bath  at  about 
140°  F.  and  place  in  it  a  well-scoured  and  wet-out  test-skein  of 
woolen  yarn;  by  means  of  the  stirring  rods  give  the  skein  a  few 
turns  in  the  liquor  so  as  to  saturate  the  fibre  thoroughly  with  the 
solution.  Then  allow  the  skein  to  hang  from  a  stirring  rod  into 
the  dye-bath,  and  heat  the  latter  gradually  to  the  boiling  point, 
turning  the  skein  from  time  to  time  so  that  it  may  dye  up  evenly. 
Do  not  maintain  the  liquor  in  a  state  of  actual  ebullition,  as  this 
will  rapidly  cause  the  fibres  of  the  wool  to  felt  together;  keep 
the  bath  just  at  a  simmer.  Continue  the  dyeing  at  this  tem- 
perature for  one-half  hour,  turning  the  skein  from  time  to  time. 
Then  remove  the  skein,  squeeze  out  the  dye  liquor,  rinse 
well  in  fresh  water  until  no  more  color  is  removed  from  the 
fibre,  then  squeeze  out  and  dry  (87).  This  experiment  rep- 
resents the  general  method  of  dyeing  nearly  all  acid  dyes  on 
wool. 

Experiment  37.  Showing  the  Use  of  Glaubersalt  in  the  Dye- 
bath.  —  Prepare  a  bath  containing  300  cc.  of  water,  4  per 
cent,  of  sulphuric  acid,  and  2  per  cent,  of  Naphthyl  Blue  Black. 
Dye  a  test-skein  of  woolen  yarn  in  this  bath,  entering  at  120°  F. 
and  gradually  raising  to  the  boil,  and  continue  at  that  temperature 
for  one-half  hour;  then  wash  and  dry  (88).  It  will  be  found  that 
the  skein  has  become  colored  rather  unevenly,  due  to  the  fact 
that  no  retarding  agent  such  as  glaubersalt  has  been  added. 
Now  prepare  a  second  bath  similar  to  the  preceding  one,  but 
also  add  20  per  cent,  of  glaubersalt,  and  then  dye  a  second  skein 

69 


7O  DYEING  AND    TEXTILE  CHEMISTRY. 

of  woolen  yarn  as  before  (89).  After  washing  and  drying, 
compare  the  evenness  of  the  colors  on  the  two  skeins. 

Experiment  38.  Showing  the  Influence  of  the  Amount  of  Acid 
in  Dyeing  with  Acid  Colors.  —  Prepare  four  dye-baths,  each 
containing  300  cc.  of  water,  20  per  cent,  of  glaubersalt,  and  2  per 
cent,  of  Formyl  Violet  loB.  To  the  first  bath  add  i  per  cent,  of 
sulphuric  acid,  to  the  second  add  2  per  cent,  of  the  acid,  to  the 
third  add  4  per  cent,  of  the  acid,  and  finally  to  the  fourth  add 
8  per  cent,  of  the  acid.  Dye  a  skein  of  woolen  yarn  in  each  of 
these  baths  in  the  usual  manner;  that  is,  entering  at  120°  F., 
gradually  raising  to  the  boil  and  dyeing  at  that  temperature  for 
one-half  hour.  After  dyeing,  wash  and  dry,  and  compare  the 
color  on  the  several  skeins  (90,  91,  92,  93).  Also  compare  the 
depth  of  color  left  in  the  respective  dye-baths  after  the  dyeing 
operation  has  been  completed. 

Experiment  39.  Showing  the  Exhaustion  of  the  Dye-bath.  — 
Prepare  a  bath  containing  300  cc.  of  water,  2  per  cent,  of  Acid 
Magenta,  4  per  cent,  of  sulphuric  acid,  and  20  per  cent,  of  glauber- 
salt. Dye  a  skein  of  woolen  yarn  in  this  bath  in  the  usual 
manner.  Squeeze  the  excess  of  dye  liquor  back  into  the  bath; 
wash  the  dyed  skein  and  dry  (94).  Then  dye  a  second  skein  of 
woolen  yarn  in  the  same  bath  without  any  further  addition  of 
dyestuff  or  chemicals,  but  fill  up  the  dye-bath  with  water  so  that 
the  volume  is  brought  back  to  the  original  point.  After  dyeing, 
squeeze  the  excess  of  liquor  into  the  bath  again,  wash  the  second 
skein  and  dry  (95).  Then  add  water  again  to  the  bath  to  bring 
it  back  to  the  original  volume,  and  dye  a  third  skein  of  woolen 
yarn  in  the  same  manner,  and  after  dyeing,  wash  and  dry  (96). 
Compare  the  color  obtained  on  the  three  skeins,  and  this  will  give 
a  good  idea  of  the  relative  exhaustion  of  the  dye-bath. 

Experiment  40.  Dyeing  Acid  Dyes  in  a  Neutral  Bath.  —  Some 
of  the  acid  dyes  are  dissociated  considerably  on  dissolving  in 
water  and  liberate  sufficient  color  acid  to  allow  of  the  dyeing  of 
the  wool  without  the  addition  of  any  acid  to  the  bath.  Prepare 
a  bath  containing  300  cc.  of  water,  10  per  cent,  of  glaubersalt, 
and  i  per  cent,  of  Orange  ENZ.  Dye  a  skein  of  woolen  yarn  in 


APPLICATION  OF  ACID  DYES.  7 1 

this  bath  in  the  usual  manner,  and  wash  and  dry  (97).  Prepare 
a  second  bath  containing  300  cc.  of  water,  10  per  cent,  of  glauber- 
salt,  i  per  cent,  of  Orange  ENZ,  and  4  per  cent,  of  sulphuric  acid. 
Dye  a  skein  of  woolen  yarn  in  this  bath  in  the  usual  manner,  and 
wash  and  dry  (98).  Compare  the  color  obtained  on  the  two 
skeins  by  these  methods. 

Experiment  41.  Dyeing  of  Alkali  Blue.  —  The  color  acids  of 
a  few  of  the  acid  dyes  are  insoluble  in  water,  and  therefore  acid 
cannot  be  added  directly  to  the  dye-bath,  but  must  be  employed 
in  a  separate  bath.  This  method  is  represented  in  the  application 
of  Alkali  Blue.  Dye  a  test-skein  of  woolen  yarn  in  a  bath  of  300  cc. 
of  water,  10  per  cent,  of  glaubersalt,  i  per  cent,  of  Alkali  Blue, 
and  2  per  cent,  of  borax.  After  boiling  for  20  minutes,  remove 
the  skein,  squeeze,  rinse  slightly  (99),  and  pass  into  a  fresh  bath 
containing  300  cc.  of  water  and  5  per  cent,  of  sulphuric  acid; 
enter  at  160°  F.,  bring  to  the  boil  and  continue  for  20  minutes 
(100).  Notice  that  the  full  blue  color  of  the  dye  is  not  developed 
until  the  material  is  treated  with  the  acid  bath.  Borax  is  a  mild 
alkali,  and  is  added  to  the  dye-bath  for  the  purpose  of  insuring  its 
remaining  perfectly  neutral.  To  show  the  effect  of  adding  the 
acid  directly  to  the  dye-bath,  prepare  a  bath  containing  300  cc. 
of  water,  10  per  cent,  of  glaubersalt,  i  per  cent,  of  Alkali  Blue,  and 
4  per  cent,  of  sulphuric  acid.  Dye  a  skein  of  woolen  yarn  in  this 
bath  in  the  usual  manner,  and  wash  and  dry  (101).  Compare 
the  result  with  that  obtained  in  the  first  method.  Also  notice 
that  the  addition  of  the  acid  to  the  bath  causes  the  precipitation 
of  the  coloring-matter. 


72  DYEING  AND    TEXTILE  CHEMISTRY. 


NOTES. 

1.  Preparation  of  the  Dye-bath.  —  For  the  dyeing  of  woolen 
yarn  there  will  be  required  about  60  times  the  amount  of  water 
or  dye  liquor  as  there  is  material  to  be  dyed;  that  is  to  say, 

1  pound  of  woolen  yarn  will  require  about  7.5  gallons  of  water 
in  the  dye-bath  (i   gallon  of  water  weighs  8J  pounds).      Silk 
will  also  require  about  the  same  proportion.     Cotton  yarn,  on 
the  other  hand,  will  require  only  about  one-half  the  amount  of 
dye  liquor  as  wool ;  that  is  to  say,  i  pound  of  cotton  may  be  dyed 
in  about  3  J  gallons  of  dye  liquor.     The  porcelain  beakers  employed 
for  the  dye-tests  should  conveniently  hold  about  300  cc.  of  water; 
consequently  they  are  of    a  convenient   size   for  the   dyeing    of 
5-gram  skeins  of  woolen  yarn  or  lo-gram  skeins  of  cotton  yarn, 
so  that  the  woolen  and  cotton  skeins  employed  for  the  tests  should 
be  supplied  in  these  weights  respectively.    For  silk,  skeins  of  about 

2  grams  weight  may  be  employed   (for  economy),  consequently 
for  such  tests  only  about  125  cc.  of  dye  liquor  should  be  used. 

2.  Calculations  Used  in  Dyeing.  —  The  amounts  of  dyestuffs 
and  chemicals  employed  in  dyeing  are  usually  expressed  in  terms 
of  percentages  on  the  weight  of  the  material  to  be  dyed.     Thus 
in  Exp.  36,  "  20  per  cent,  of  glaubersalt,  4  per  cent,  of  sulphuric 
acid,  and  i  per  cent,  of  Acid  Magenta"  are  called  for;  this  would 
mean  that  the  actual  amounts  of  the  substances  to  be  taken 
are  to  be  the  respective  percentages  on  the  weight  of  the  yarn 
dyed,  which  in  this  case  is  5  grams.     Therefore  we  have: 

5  grams  X  .04  =  0.20  gram  for  the  sulphuric  acid, 
5  grams  X  .20  =  i.oo  gram  for  the  glaubersalt, 
5  grams  X  .01  =  0.05  gram  for  the  dyestuff. 

As  these  are  rather  small  amounts  to  be  continually  weighing 
out,  it  is  best  to  have  the  chemicals  and  dyestuffs  employed 
in  the  dye-tests  made  up  in  solutions  of  such  strength  that 
convenient  volumes  will  contain  the  required  amounts 
as  needed  for  the  preparation  of  the  dye-baths.  As  4  per 


APPLICATION  OF  ACID  DYES.  73 

cent,  is  the  customary  amount  of  sulphuric  acid  to  employ,  a 
convenient  solution  would  be  one  of  such  strength  that  10  cc. 
would  contain  4  per  cent,  of  the  acid  on  5  grams  (this  being  the 
weight  of  the  woolen  yarn  employed  in  all  the  tests).  To  prepare 
one  litre  or  1000  cc.  of  this  solution,  proceed  as  follows: 

10  cc.  is  to  contain  4  per  cent,  on  5  grams  =  0.2  gram  acid. 
1000  cc.  would  therefore  contain  20  grams  acid. 

As  the  commercial  concentrated  sulphuric  acid  has  a  density  of 
about  1.84  (i.e.,  i  cc.  weighs  1.84  grams),  20  grams  by  weight  of 
the  acid  would  be  equivalent  to  20  -v-  1.84  =  11.9  cc.  Hence 
the  solution  should  contain  11.9  cc.  of  the  concentrated  sulphuric 
acid  per  litre.  The  solution  of  glaubersalt  may  be  prepared  in 
a  similar  manner.  A  convenient  strength  is  one  containing 
20  per  cent,  of  the  salt  on  5  grams  in  10  cc.,  which  would  be 
i  gram  in  10  cc.,  or  100  grams  per  litre.  A  convenient  strength 
for  the  solutions  of  dyestuff  s  is  5  grams  per  litre;  hence  i  per  cent, 
on  5  grams  would  be  equivalent  to  10  cc.  of  the  solution.  For  a 
lo-gram  skein,  where  cotton  yarn  is  employed  in  the  tests,  20  cc. 
would  be  equivalent  to  i  per  cent. 

3.  Function  of  the  Chemicals  Employed  in  Dyeing  Acid 
Colors.  —  These  chemicals  are  mostly  confined  to  sulphuric  acid 
and  glaubersalt.  As  already  explained  under  the  general  theory 
of  dyeing,  the  sulphuric  acid  is  used  for  the  purpose  of  liberating 
the  color-acid  of  the  dyestuff  so  that  it  may  more  readily  combine 
with  the  basic  component  of  the  fibre;  hence  the  addition  of  the 
acid  facilitates  the  dyeing  and  increases  the  exhaustion  of  the 
bath.  Some  acid  dyes  naturally  require  more  acid  than  others 
to  give  the  same  degree  of  exhaustion,  but  4  per  cent,  (on  the 
weight  of  the  wool)  appears  to  be  ample  for  almost  all  cases. 
The  dyer  does  not  vary  the  amount  of  acid  with  each  individual 
dyestuff  or  variation  in  quantity  of  dyestuff  used,  but  adheres 
to  the  fixed  quantity  of  4  per  cent.  Sometimes  a  better  degree  of 
exhaustion  may  be  obtained  by  the  addition  of  a  further  quantity 
(about  2  per  cent.)  of  acid  near  the  completion  of  the  dyeing 


74  DYEING  AND    TEXTILE  CHEMISTRY. 

operation.  Some  of  the  acid  dyes  do  not  require  the  addition  of 
such  a  strong  acid  as  sulphuric  to  liberate  the  color-acid,  but  give 
very  good  results  with  a  milder  acid,  such  as  the  organic  acetic 
acid.  Formic  acid  may  also  be  used.  Such  colors  are  especially 
useful  for  the  dyeing  of  wool-cotton  fabrics,  as  the  cotton  is  not 
injured  by  the  acetic  or  formic  acid.  Nearly  all  of  the  acid  colors 
are  slightly  dissociated  on  dissolving  in  water;  that  is  to  say,  a  small 
amount  of  the  free  color-acid  is  formed ;  hence  a  certain  degree  of 
dyeing  takes  place  even  without  the  addition  of  acid.  Some  of 
the  acid  dyes  are  largely  dissociated  in  solution,  and  consequently 
these  may  be  dyed  in  a  neutral  bath.  Such  colors  are  also  useful 
for  wool-cotton  dyeing.  Therefore  the  acid  dyes  may  be  divided 
into  groups  with  reference  to  the  required  acidity  of  the  dye- 
bath: 

(a)  Dyes  which  may  be  applied  in  a  neutral  bath. 

(b)  Dyes  which  require  a  slightly  acid  bath;  usually  acetic 
acid  being  employed. 

(c)  Dyes  which  require  a  bath  acidulated  with  sulphuric  acid. 

The  glaubersalt  used  in  the  dye-bath  may  exert  an  influence 
in  several  different  ways: 

(a)  In   mechanically  retarding  the   interaction  between   the 
color-acid  and  the  fibre. 

(b)  In  chemically  retarding  the  liberation  of  the  color-acid 
from  the  dye-salt. 

(c)  In  affecting  the.  solubility  of  the  dyestuff  in  the  solution. 

The  first  effect  has  been  considered  under  the  general  theory 
of  dyeing,  and  is  very  likely  the  chief  influence  exerted  by  the 
glaubersalt.  There  is  a  considerable  possibility,  however,  that 
a  chemical  action  may  come  into  play.  It  is  a  well-established 
principle  in  chemistry  that  when  one  of  the  products  of  a  chemical 
reaction  is  present  in  the  solution,  the  rapidity  and  extent  of 
this  reaction  will  be  reduced.  Now,  in  the  interaction  between 
sulphuric  acid  and  the  dyestuff  (which  is  generally  the  sodium 
salt  of  the  color-acid)  glaubersalt  is  formed;  hence,  if  a  relatively 


75 

large  proportion  of  glaubersalt  is  already  present,  the  reaction 
between  the  acid  and  the  dyestuff  will  be  considerably  retarded. 
Just  to  what  extent  this  influence  of  the  glaubersalt  affects  the 
even  dyeing  of  the  acid  colors  is  a  question;  but  it  is  doubtful  if 
it  is  as  important  as  the  preceding  influence.  As  to  the  degree  in 
which  the  glaubersalt  affects  the  solubility  of  the  dyestuff  in  the 
solution,  it  may  be  stated  that  this  must  be  rather  limited,  when 
it  is  considered  that  both  the  dyestuff  and  the  glaubersalt  are  in 
rather  dilute  solutions.  The  general  effect  of  the  addition  of 
glaubersalt  to  a  dyestuff  solution  would  be  to  lessen  the  solubility 
of  the  dye;  but  in  order  for  this  effect  to  be  marked  the  concen- 
tration of  the  glaubersalt  in  the  solution  would  have  to  be  rather 
high.  If  the  glaubersalt  did  act  in  this  manner  in  the  ordinary 
dye-bath,  the  effect  would  be  to  throw  the  dyestuff  out  of  solution 
and  hence  to  promote  uneven  rather  than  level  dyeing;  whereas 
we  know  the  opposite  to  be  the  case.  Furthermore,  many  of  the 
acid  dyes  may  be  partially  stripped  from  the  fibre  by  boiling  in 
a  bath  containing  glaubersalt;  much  more  of  the  dyestuff  being 
dissolved  than  if  plain  boiling  water  were  used. 

Glaubersalt  is  the  common  name  for  crystallized  sodium 
sulphate;  it  has  the  chemical  formula  Na.jSO4 .  ioH2O.  Calcined 
or  desiccated  glaubersalt  has  the  water  of  crystallization  removed 
by  heating;  it  is  a  white  amorphous  powder,  having  the  formula 
Na2SO4.  About  44  parts  of  desiccated  glaubersalt  are  equivalent 
to  100  parts  of  the  crystalline  salt. 

4.  General  Characteristics  of  the  Acid  Dyes.  —  These  colors 
are  the  principal  dyes  employed  for  the  dyeing  of  woolen  materials, 
especially  yarns  and  piece-goods.  Most  of  them  are  level- 
dyeing;  and  their  general  fastness  to  washing  and  light  is  good, 
though  the  fastness  varies  largely  with  the  individual  members. 
The  acid  dyes,  as  a  rule,  are  cheap  compared  with  the  other 
classes  of  dyestuffs  and  considering  their  high  coloring  power. 
In  this  latter  respect,  however,  they  are  not  equal  to  the  basic 
dyes,  though  these  are  more  costly.  In  range  of  color  the  acid 
dyes  are  quite  varied,  representatives  of  almost  every  color  being 


76  DYEING  AND    TEXTILE  CHEMISTRY. 

available.  Water  of  ordinary  hardness  does  not  have  much 
effect  on  the  acid  dyes,  and  in  the  dye-bath  any  tendency  of  hard 
water  to  precipitate  these  colors  is  prevented  by  the  presence  of 
acid.  Material  dyed  with  the  acid  colors  should  be  well  washed 
after  coming  from  the  dye-bath,  especially  if  heavy  shades  are 
used,  otherwise  the  color  may  show  unnecessary  bleeding  on 
scouring,  or  may  have  the  defect  of  rubbing  or  "crocking." 
Should  an  acid  color  show  any  tendency  towards  dyeing  unevenly, 
the  following  precautions  should  be  observed: 

(a)  Start  the  dye-bath  at  a  low  temperature  and  heat  to  the 
boiling  point  only  very  gradually. 

(b)  Do  not  add  any  acid  until  the  goods  have  been  worked  in 
the  dye-bath  for  some  time,  and  then  add  the  acid  in  several 
portions  during  the  dyeing. 

(c)  Be  sure  that  the  dyestuff  is  thoroughly  dissolved  and  add 
the  solution  in  several  portions  during  the  dyeing. 

(d)  Do  not  use  too  "short"  a  dye-bath,  that  is,  one  containing 
too  little  water. 

The  acid  dyes,  as  a  rule,  exhaust  fairly  well,  though  this  quality 
varies  with  individual  members  of  the  group.  The  exhaustion  of 
the  dye-bath  may  usually  be  considerably  increased  by  the  addi- 
tion of  extra  acid  towards  the  end  of  the  dyeing  operation.  In  case 
the  bath  does  not  exhaust  well,  it  should  be  kept  as  a  "standing 
kettle,"  that  is,  preserved  for  further  use  and  freshened  up  by 
the  addition  of  the  necessary  amount  of  dyestuff.  Of  course  the 
poorer  the  exhaustion  of  the  dye-bath  the  less  will  be  the  amount 
of  the  second  addition  of  dyestuff.  Generally  speaking,  with  the 
third  or  fourth  successive  bath,  the  amount  of  dyestuff  to  be 
added  each  time  will  become  constant  in  order  to  produce  the 
same  shade.  Most  of  the  acid  dyes  will  give  a  "full  shade" 
(in  a  starting  bath)  with  about  3  to  4  per  cent,  of  color.  By  a 
full  shade  is  meant  the  maximum  depth  of  color  given  by  a 
dyestuff. 

5.  Useful  Data  for  Calculations  in  Dyeing.  —  To  find  the  capa- 
city of  a  rectangular  tank:  Multiply  the  length  by  the  breadth 


APPLICATION  OF  ACID  DYES. 


77 


by  the  depth  (in  feet),  then  multiply  this  product  by  7.5  (the 
number  of  gallons  in  a  cubic  foot) .  The  result  will  be  the  capa- 
city of  the  tank  in  gallons. 

To  find  the  capacity  of  a  circular  tank:  Find  the  square  of 
half  the  diameter  (in  feet) ,  multiply  by  V-  (an  approximation  to 
TT  =  3.1416),  then  multiply  by  the  depth  (in  feet),  and  finally 
multiply  by  7.5.  The  result  will  be  the  capacity  of  the  tank  in 
gallons.  A  shorter  approximation  to  the  same  result  is  as 
follows :  square  the  diameter,  multiply  by  the  height,  and  then  by 
the  factor  5.9. 

To  convert  grams  per  litre  into  ounces  per  gallon:  Since  one 
gallon  is  equivalent  to  3!  litres,  and  one  ounce  is  equal  to 
28.3  grams,  multiply  the  number  of  grams  per  litre  by  3!  and 
divide  by  28.3.  A  briefer  formula  is  to  multipy  grams  per  litre 
by  the  factor  0.133. 

To  convert  grams  per  kilogram  into  ounces  per  100  pounds: 
Multiply  by  the  factor  1.6. 


Grams 

Grams  per 

Per  gallon. 

Grams 

Grams 

Per  gallon. 

per  litre. 

gallon. 

Lbs. 

Ozs. 

Grns. 

per  litre. 

per  gallon. 

Lbs. 

Ozs. 

Grns. 

I 

3.785 

58 

17 

64.35 

2 

112 

2 

7-570 

116 

18 

68.14 

2 

170 

3 

n-355 

*74 

19 

71.92 

2 

228 

4 

15.140 

232 

20 

75.70 

2 

286 

5 

18.92 

290 

30 

H3.55 

3 

429 

6 

22.71 

348 

40 

I5L4 

5 

l65 

7 

26.  50 

406 

5° 

189.2 

6 

278 

8 

30.28 

27 

60 

227.1 

7 

421 

9 

34-07 

85 

70 

265.0 

9 

127 

10 

37-85 

143 

80 

302.8 

10 

270 

ii 

41.63 

201 

90 

340-7 

ii 

413 

12 

45-42 

259 

IOO 

378.5 

13 

119 

15 

49-21 

317 

2OO 

757-0 

I 

10 

238 

14 

53-oo 

375 

300 

ii35-5 

2 

7 

357 

15 

56.76 

433 

400 

1514.0 

3 

5 

39 

16 

60.56 

2 

54 

500 

1892.0 

4 

2 

158 

EXAMPLE.  —  A  solution  of  sulphuric  acid  of  i°  Tw.  density 
contains  8  grams  of  the  acid  per  litre.  Reference  to  the  above 
table  shows  that  this  amount  is  equivalent  to  i  oz.  27  grns.  per 
gallon. 


DYEING  AND    TEXTILE  CHEMISTRY. 


To  convert  percentage  of  color  into  the  corresponding  quantity 
per  100  pounds  of  goods: 


Per  cent. 

Per  100  Ibs. 

Per  cent. 

Per  100  Ibs. 

Per  cent. 

Per  100  Ibs. 

Ozs. 

Grns. 

Ozs. 

Grns. 

Ozs. 

Grns. 

O.OOI 

7 

0.30 

4 

35° 

0.68 

10 

385 

O.O02 

14 

0.31 

4 

420 

0.69 

n 

18 

0.003 

21 

0.32 

5 

53 

0.70 

II 

88 

0.004 

28 

o-33 

5 

123 

0.71 

II 

158 

0.005 

35 

0.34 

5 

193 

0.72 

II 

228 

0.006 

42  t 

o-35 

5 

263 

°-73 

II 

298 

0.007 

49 

0.36 

5 

333 

0.74 

II 

368 

0.008 

56 

o-37 

5 

403 

Q-75 

12 

0 

0.009 

63 

0.38 

6 

35 

0.76 

12 

70 

O.OI 

70 

o-39 

6 

I05 

0.77 

12 

140 

O.O2 

140 

0.40 

6 

J75 

0.78 

12 

2IO 

0.03 

210 

0.41 

6 

245 

0.79 

12 

280 

O.O4 

280 

0.42 

6 

3i5 

0.80 

12 

35° 

O.O5 

35<> 

0.43 

6 

385 

0.81 

12 

420 

0.06 

420 

0.44 

7 

18 

0.82 

13 

53 

0.07 

53 

0-45 

7 

88 

0.83 

13 

123 

0.08 

123 

0.46 

7 

158 

0.84 

13 

i93 

O.OQ 

iQ3 

0.47 

7 

228 

0.85 

13 

263 

0.  10 

263 

0.48 

7 

298 

0.86 

13 

333 

O.  II 

333 

0.49 

7 

368 

0.87 

J3 

403 

0.12 

403 

0.50 

8 

0 

0.88 

14 

35 

O.I3 

2 

35 

0.51 

8 

70 

0.89 

14 

105 

0.14 

2 

106 

0.52 

8 

140 

0.90 

14 

i75 

O.IS 

2 

176 

°-53 

8 

210 

0.91 

14 

245 

o.  16 

2 

246 

0.54 

/  8 

280 

0.92 

14 

3i5 

0.17 

2 

316 

°-55 

8 

350 

°-93 

14 

385 

o.  18 

2 

386 

o.  56 

8 

42O 

0.94 

15 

18 

0.19 

3 

18 

o-57 

9 

53 

°-95 

15 

88 

o.  20 

3 

88 

0.58 

9 

123 

0.96 

15 

158 

0.  21 

3 

158 

°-59 

9 

i93 

0.97 

15 

228 

O.  22 

3 

229 

o.  60 

9 

263 

0.98 

15 

298 

0.23 

3 

299 

o.  61 

9 

333 

0.99 

15 

368 

o.  24 

3 

369 

o.  62 

9 

403 

I.OO 

16 

o 

o.  25 

4 

0 

o.  63 

10 

35 

2. 

32 

0 

o.  26 

4 

70 

o.  64 

10 

I05 

3- 

48 

o 

0.27  . 

4 

140 

o.  65 

10 

i75 

4- 

64 

0 

0.28 

4 

210 

0.66 

10 

.245 

5- 

80 

o 

o.  29 

4 

280 

o.  67 

10 

3i5 

6. 

96 

0 

EXAMPLE. — There  is  required  2.16  per  cent,  of  dyestuff  for 
100  pounds  of  goods.  Reference  to  the  above  table  shows  for 
100  pounds  of  goods  : 

2       per  cent,  is  32  ozs. 
0.16  per  cent,  is    2  ozs.  246  grns. 
Hence  2.16  per  cent,  is  34  ozs.  246  grns. 


APPLICATION  OF  ACID  DYES. 


79 


To  convert  cubic  centimeters  of  test  solutions  containing  one 
gram  of  dyestuff  dissolved  in  one  litre  into  corresponding  percent- 
ages for  10-gram  test-skeins  and  weights  of  dyestuff  per  100  pounds 
of  goods: 


i 
*o  . 

"o-ji 

d 

Per 
cent, 
on  10 

grams. 

Weight  per 
100  Ibs. 

Ig 
"3-2 

6 

Per 
cent, 
on  10 

grams. 

Weight  per 
100  Ibs. 

A 

Is 

"o'43 

6 

Per 
cent, 
on  10 

grams. 

Weight  per 
too  Ibs. 

Lbs. 

Ozs. 

Grns. 

Lbs. 

Ozs. 

Grns. 

Lbs. 

Ozs. 

Grns. 

i 

O.  OI 

7o 

46 

0.46 

7 

157 

91 

0.91 

14 

245 

2 

O.O2 

140 

47 

0.47 

7 

227 

92 

0.92 

14 

315 

3 

0.03 

210 

48 

0.48 

7 

297 

93 

o-93 

14 

385 

4 

O.O4 

280 

49 

0.49 

7 

367 

94 

0.94 

15 

17 

5 

O.05 

35° 

5° 

o.  50 

8 

O 

95 

°-95 

15 

87 

6 

O.O6 

420 

5i 

0.51 

8 

70 

96 

0.96 

15 

157 

7 

O.O7 

I 

52 

52 

0.52 

8 

140 

97 

0.97 

15 

227 

8 

0.08 

I 

122 

53 

°-53 

8 

2IO 

98 

0.98 

15 

297 

9 

O.O9 

I 

192 

54 

0.54 

8 

280 

99 

0.99 

IS 

367 

10 

0.  10 

I 

262 

55 

°-55 

8 

350 

IOO 

.00 

o 

O 

ii 

0.  II 

I 

332 

56 

o.  56 

8 

42O 

101 

.01 

o 

7° 

12 

0.  12 

i 

402 

57 

o-57 

9 

52 

1  02 

.02 

0 

140 

J3 

0.13 

2 

35 

58 

0.58 

9 

122 

103 

•03 

0 

2IO 

14 

o.  14 

2 

I05 

59 

°-59 

9 

192 

104 

.04 

o 

280 

15 

0.15 

2 

i75 

60 

o.  60 

9 

262 

I05 

•05 

o 

35° 

16 

o.  16 

2 

245 

61 

0.61 

9 

333 

1  06 

.06 

0 

42O 

17 

o.  17 

2 

3i5 

62 

o.  62 

9 

402 

107 

.07 

I 

S* 

18 

0.18 

2 

385 

63 

0.63 

10 

35 

1  08 

.08 

I 

122 

T9 

o.  19 

3 

17 

64 

o.  64 

10 

105 

109 

.09 

I 

192 

20 

o.  20 

3 

87 

65 

o.  65 

IO 

175 

no 

.  10 

I 

262 

21 

0.21 

3 

i57 

66 

0.66 

IO 

245 

in 

.  ii 

I 

332 

22 

0.  22 

3 

227 

67 

o.  67 

10 

3i5 

112 

.  12 

I 

402 

23 

0.23 

3 

297 

68 

0.68 

10 

385 

"3 

•*3 

2 

35 

24 

0.24 

3 

367 

69 

o.  69 

II 

J7 

114 

.14 

2 

io5 

25 

0.25 

4 

0 

70 

o.  70 

II 

87 

H5 

•15 

2 

*75 

26 

o.  26 

4 

70 

7i 

0.71 

II 

J57 

116 

.16 

2 

245 

27 

0.27 

4 

140 

72 

0.72 

II 

227 

117 

•17 

2 

3i5 

28 

0.28 

4 

210 

73 

°-73 

II 

297 

118 

.18 

2 

385 

2Q 

o.  29 

4 

280 

74 

0.74 

II 

367 

119 

.19 

3 

i7 

3° 

0.30 

4 

350 

75 

Q-75 

12 

0 

I2O 

.  20 

3 

87 

31 

0.31 

4 

420 

76 

o.  76 

12 

70 

121 

.  21 

3 

i57 

32 

0.32 

5 

52 

77 

0.77 

12 

140 

122 

.  22 

3 

227 

33 

°-33 

5 

122 

78 

0.78 

12 

2IO 

123 

•23 

3 

297 

34 

o-34 

5 

192 

79 

0.79 

12 

280 

124 

.24 

3 

367 

35 

°-35 

5 

262 

80 

0.80 

12 

35° 

I25 

•25 

4 

0 

16 

0.36 

5 

332 

81 

0.81 

12 

420 

126 

.26 

4 

70 

37 

o-37 

5 

402 

82 

0.82 

13 

52 

127 

•27 

4 

140 

38 

0.38 

6 

35 

83 

0.83 

13 

122 

128 

.28 

4 

2IO 

39 

°-39 

6 

I05 

84 

0.84 

13 

192 

129 

.29 

4 

280 

40 

0.40 

6 

*75 

85 

0.85 

!3 

262 

130 

•30 

4 

35° 

4i 

0.41 

6 

245 

86 

0.86 

13 

332 

I3I 

•31 

4 

420 

42 

0.42 

6 

3i5 

87 

0.87 

13 

4O2 

132 

•32 

5 

52 

43 

o-43 

6 

385 

88 

0.88 

14 

35 

i33 

•33 

5 

122 

44 

0.44 

7 

i7 

89 

0.89 

14 

i°5 

i34 

,  -34 

5 

192 

4"> 

o-4S 

7 

87 

90 

0.90 

14 

175 

!35 

•35 

5 

262 

8o 


DYEING   AND    TEXTILE   CHEMISTRY. 


A 

Per 

Weight  per 

| 

Per 

Weight  per 

$ 

Per 

Weight  per 

1  a 

cent. 

100  Ibs. 

Sd 

cent. 

100  Ibs. 

Sci 

cent. 

100  Ibs. 

•8-8 

on  10 

•3-2 

on  10 

•sj 

on  10 

d 

grams. 

Lbs. 

Ozs. 

Grns. 

6 

grams. 

Lbs. 

Ozs. 

jrns. 

u 

o 

grams. 

Lbs. 

Ozs. 

Grns. 

136 

.36 

5 

332 

158 

•58 

9 

122 

1  80 

.80 

I 

12 

350 

i37 

•37 

5 

402 

J59 

•59 

9 

192 

181 

.81 

I 

12 

420 

138 

•38 

6 

35 

160 

.60 

9 

262 

182 

.82 

13 

52 

i39 

•39 

6 

i°5 

161 

.61 

9 

332 

183 

•83 

13 

122 

140 

.40 

6 

i75 

162 

.62 

9 

402 

184 

.84 

13 

192 

141 

.41 

6 

245 

163 

•63 

10 

35 

185 

•85 

13 

262 

142 

.42 

6 

3J5 

164 

•  64 

10 

i°5 

1  86 

.86 

13 

332 

143 

•43 

6 

385 

165 

•65 

10 

175 

187 

•87 

13 

402 

144 

•44 

7 

i7 

1  66 

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10 

245 

1  88 

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14 

35 

145 

•45 

7 

87 

167 

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IO 

3i5 

189 

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14 

105 

146 

.46 

7 

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1  68 

.  68 

IO 

385 

190 

.90 

14 

i75 

147 

•47 

7 

227 

169 

.69 

II 

i7 

191 

.91 

14 

245 

148 

.48 

7 

297 

170 

.70 

II 

87 

192 

.92 

14 

3i5 

149 

•49 

7 

367 

171 

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14 

385 

15° 

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8 

o 

172 

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227 

194 

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15 

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151 

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8 

70 

173 

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297 

195 

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87 

152 

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174 

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367 

196 

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15 

157 

153 

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8 

210 

175 

•75 

12 

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197 

•97 

15 

227 

154 

•54 

8 

280 

176 

.76 

12 

70 

198 

.98 

15 

297 

155 

•55 

8 

35° 

177 

•77 

12 

140 

199 

•99 

15 

367 

156 

•56 

8 

420 

178 

•78 

12 

210 

200 

2.00 

2 

0 

0 

157 

•57 

9 

52 

179 

•79 

12 

280 

300 

3.00 

3 

0 

o 

EXAMPLE.  —  To  obtain  0.67  per  cent,  of  dyestuff  on  a  lo-gram 
test-skein  of  wool  or  cotton,  when  the  solution  contains  i  gram 
of  dyestuff  per  litre,  it  would  be  necessary  to  take  67  cc.  of  the 
solution;  and  for  the  dyeing  of  100  pounds  of  goods  this  would 
be  equivalent  to  10  ounces  315  grains  of  dyestuff. 

In  case  a  5-gram  test-skein  is  used,  the  above  figures  in  the 
percentage  and  weight  columns  are  to  be  multiplied  by  2. 
For  instance,  1.34  per  cent,  of  dyestuff  would  be  equivalent  to 
67  cc.  of  the  solution,  or  to  i  pound  5  ounces  193  grains  on 
100  pounds  of  material. 

In  case  the  dyestuff  solution  contains  more  than  i  gram  per 
litre,  it  will  be  necessary  to  multiply  the  figures  in  the  percent- 
age and  weight  columns  by  the  number  of  grams  per  litre  of  the 
solution.  For  instance,  if  the  solution  contains  5  grams  per 
litre,  67  cc.  would  be  equivalent  to  3.35  per  cent.,  or  to  3  pounds 
5  ounces  262  grains  on  100  pounds,  if  a  lo-gram  test-skein  is  used. 


APPLICATION  OF  ACID  DYES. 


81 


If  a  5-gram  test-skein  be  used,  67  cc.  of  such  a  solution  would 
be  equivalent  to  6.70  per  cent.,  or  to  6  pounds  n  ounces  87  grains 
on  100  pounds  of  goods. 

To  convert  percentage  of  color  (on  100  pounds  of  goods}  into 
quantity  of  standard  solution  of  4  ounces  of  dry  color  per  gallon: 


Solution  of  4 

ozs.  per  gallon. 

Lbs. 

Per  cent. 

Quarts. 

Pints. 

Gills. 

Noggins. 

& 

I 

i 

XJL 

Y 

2 

I 

I 

zi 

i 

IOO' 

| 

8 

IOO 

j 

16 

2  noggins  =  i  gill  2  pints  =  i  quart 

4  gills  =  i  pint  4  quarts  =  i  gallon 

Convenient  data  regarding  quantities  of  water  based  on  United 
States  gallon: 

i  gallon  =23 1.      cubic  inches  =   8.3      pounds 
i  quart=   57.75      "          "     =   2.1  " 

i  pint=   28.88      "          "     =    i.o 
i  gill=     7.22      "          "     =     .25 

i  cubic  foot  =    1728      "          "     =62.5  "      =  7.5  gallons 

i  cubic  inch  =     .036 

Comparative  Strength  of  Different  Chemicals. 

100  parts  by  weight  of  sal  soda  (Na2CO3.io  H2O)  is  equivalent 
to  about  37  parts  of  so  da  ash  (Na2CO3). 

loo  parts  of  soda  ash  is  equivalent  to  270  parts  sal  soda. 

100  parts  crystallized  glaubersalt  (Na2SO4.io  H2O)  is  equivalent 
to  44  parts  of  calcined  glaubersalt  (Na-jSOJ. 

100  parts  of  calcined  glaubersalt  is  equivalent  to  227  parts  of 
crystallized  glaubersalt. 

loo  parts  of  alum  (10.76  per  cent.  ALjOg)  has  the  same  practical 
value  as  60  parts  of  aluminium  sulphate  (18  per  cent.  A12O3). 

loo  parts  of  aluminium  sulphate  are  equivalent  to  170  parts 
alum. 


82  DYEING  AND    TEXTILE  CHEMISTRY. 

ioo  parts  of  sulphuric  acid  (168°  Tw.)  correspond  to  220  parts 
of  hydrochloric  acid  (32°  Tw.)  or  to  400  parts  of  acetic  acid 

(9°  Tw.). 

ioo  parts  of  hydrochloric  acid  correspond  to  45  parts  of  sul- 
phuric acid  or  to  175  parts  of  acetic  acid. 

ioo  parts  of  acetic  acid  correspond  to  26  parts  of  sulphuric 
acid  or  to  57  parts  of  hydrochloric  acid. 

SAMPLES. 

87.  Representing  the  application  of  acid  dyes  to  wool. 

88.  Dyed  without  glaubersalt. 

89.  Dyed  with  glaubersalt. 

90.  Dyed  with  i  per  cent,  sulphuric  acid. 

91.  Dyed  with  2  per  cent,  sulphuric  acid. 

92.  Dyed  with  4  per  cent,  sulphuric  acid. 

93.  Dyed  with  8  per  cent,  sulphuric  acid. 

94.  First  dyeing  from  bath. 

95.  Second  dyeing  from  bath. 

96.  Third  dyeing  from  bath. 

97.  Dyed  in  a  neutral  bath. 

98.  Dyed  with  acid  in  bath. 

99.  Alkali  blue  before  acid  treatment. 

100.  Alkali  blue  after  treatment  with  acid. 

101.  Alkali  blue  dyed  with  acid  in  the  bath. 

QUIZ  6. 

131.  Outline  briefly  the  general  method  of  dyeing  acid  colors  on  wool. 

132.  Explain  the  function  of  the  acid  and  the  glaubersalt  in  the  dye-bath. 
133-  What  conditions  of  temperature  should  be  maintained  in  dyeing? 

Explain  the  influence  of  the  temperature  of  the  bath  on  the  dyeing  process. 

134.  About  what  length  of  time  is  required  for  the  dyeing  to  be  completed  ? 
What  precautions  should  be  taken  in  working  the  material  in  the  dye-bath  to 
prevent  felting  ? 

i35«  Why  should  the  material  after  dyeing  be  well  washed?  Does  hard 
water  have  much  influence  in  the  dyeing  of  acid  colors  ? 

136.  Are  the  acid  colors  much  employed  for  the  dyeing  of  wool?  Give  the 
general  characteristics  of  the  acid  colors  with  respect  to  level  dyeing,  general 
fastness,  cheapness,  and  range  of  colors. 

137-  Discuss  the  various  precautions  to  be  adopted  for  the  production  of 
even  colors  in  the  dyeing  with  acid  dyes. 


APPLICATION  OF  ACID  DYES.  83 

138.  Explain  the  chemical  and  physical  action  of  the  glaubersalt  in  the 
dye-bath  in  promoting  even  colors  and  good  penetration. 

139.  What  is  glaubersalt?    What  is  meant  by  desiccated  glaubersalt? 
What  quantity  of  glaubersalt  is  usually  employed  in  dyeing  ? 

140.  From  your  test  to  show  the  influence  of  the  amount  of  acid  in  the  dye- 
bath  on  the  quality  of  the  resulting  color,  what  would  you  conclude  as  to  the 
proper  amount  of  acid  to  be  employed  ? 

"141.  What  is  meant  by  the  "exhaustion"  of  the  dye-bath?  Do  the  acid 
dye-baths,  as  a  rule,  exhaust  well  ?  How  may  the  relative  exhaustion  of  the 
dye- bath  be  shown  ? 

142.  What  is  meant  by  a  "standing  kettle"?    What  influence  does  the 
exhaustion  of  the  dye-bath  have  on  the  amount  of  dyestuff  to  be  added  for 
successive  dyeings  from  the  same  kettle  ? 

143.  In  what  manner  may  the  exhaustion  of  the  dye-bath  be  increased? 
What  is  meant  by  a  "full  shade"  of  a  dyestuff?    What  percentage  of  acid  dye 
is  usually  necessary  to  give  a  full  shade  in  the  first  bath  ? 

144.  Explain  why  some  of  the  acid  dyes  may  be  applied  to  wool  in  a  neutral 
bath.     Is  the  exhaustion  good  in  such  cases?     Under  what  circumstances 
would  material  be  likely  to  be  dyed  with  acid  colors  in  a  neutral  bath  ? 

145.  How  does  the  application  of  Alkali  Blue  differ  from  that  of  other  acid 
dyes  ?    Why  cannot  the  acid  be  added  directly  to  the  dye-bath  ? 

146.  What  is  the  purpose  of  adding  borax  to  the  dye-bath  when  Alkali  Blue 
is  used?    What  is  borax?    What  is  its  chemical  character? 

147.  Why  is  it  necessary  to  after-treat  Alkali  Blue  with  an  acid  bath? 
What  color  is  the  material  after  dyeing  in  the  first  bath,  and  what  color  does  it 
become  when  passed  into  the  acid  bath  ? 

148.  What  is  the  effect  of  dyeing  Alkali  Blue  with  acid  added  directly  to 
the  dye-bath?    Are  there  many  acid  dyes  which  require  to  be  dyed  in  the 
manner  of  Alkali  Blue  ? 

149.  What  proportion  should  exist  between  the  amount  of  woolen  yarn  to 
be  dyed  and  the  amount  of  dye  liquor  used  ?     What  proportion  for  silk  ? 
What  proportion  for  cotton  ? 

150.  How  many  gallons  of  water  are  required  for  the  dyeing  of  i  pound  of 
woolen  yarn  ?     How  many  pounds  of  water  are  in  the  United  States  gallon  ? 
In  the  English  gallon  ? 

151.  Suppose  it  is  required  to  dye  100  pounds  of  woolen  yarn,  and  the  dye- 
vat  is  3  feet  deep  by  2  feet  wide;  how  long  would  it  have  to  be  to  contain  the 
necessary  dye  liquor?     (i  cubic  foot  of  water  weighs  62.5  pounds.) 

152.  What  weights  of  woolen  and  cotton  test-skeins  may  be  conveniently 
dyed  in  a  beaker  holding  300  cc.  of  water  ?     How  much  water  would  be  required 
for  the  dyeing  of  test-skeins  of  silk  weighing  2  grams  ? 

153.  In  what  manner  are  the  amounts  of  dyestuffs  and  chemicals  calculated 
in  the  preparation  of  dye-baths  ? 


84  DYEING  AND   TEXTILE  CHEMISTRY. 

154.  If  100  pounds  of  woolen  yarn  were  to  be  dyed  by  the  formula  given  in 
Exp.  36,  what  weights  of  glaubersalt,  acid,  and  dyestuff  would  be  required  ? 
How  many  pints  of  sulphuric  acid  would  be  required?    (i  pint  of  water  is 
equivalent  to  i  pound.) 

155.  If  56  pounds  of  woolen  yarn  are  to  be  dyed,   using   the  following 
amounts  of  dyestuffs: 

0.75  per  cent.  Acid  Magenta, 

1. 1 2  per  cent.  Orange  ENZ, 

0.08  per  cent.  Formyl  Violet, 

calculate  the  quantities  of  these  dyes  in  pounds,  ounces,  and  grains  which 
would  be  required.  Calculate  the  quantities  in  terms  of  grams.  (See  Appen- 
dix for  tables  of  measures  and  weights.) 

156.  How  would  you  prepare  a  solution  of  sulphuric  acid  of  such  strength 
that  10  cc.  would  be  equivalent  to  4  per  cent,  on  5  grams?     How  would  you 
prepare  such  a  solution  that  5  cc.  would  be  equivalent  to  6  per  cent,  on  8 
grams  ? 

157.  If  a  solution  of  dyestuff  contains  5  grams  of  dry  color  per  litre,  how 
many  cubic  centimeters  would  be  equivalent  to  3.5  per  cent,  on  5  grams  ?    To 
2.75  per  cent,  on  10  grams? 

158.  If  a  2-gram  skein  of  silk  is  employed  for  a  dye-test  the  dye  solution 
should  contain  how  many  grams  per  litre  in  order  that  10  cc.  may  be  equivalent 
to  i  per  cent,  in  dyeing  the  silk  ? 

159.  If  a  solution  of  dyestuff  is  used  containing  4  ounces  per  gallon,  how 
much  would  be  required  for  i  per  cent,  on  10  pounds  of  yarn  ?   For  one-quarter 
per  cent,  on  25  pounds?    For  2 \  per  cent,  on  45  pounds ?     (Give  the  result  in 
terms  of  gallons,  quarts,  pints,  gills,  and  noggins.) 

1 60.  How  many  grams  of  dyestuff  would  be  needed  to  give  0.08  per  cent,  on 
125  kilos?     For  1.25  per  cent,  on  25  kilos?     For  one-quarter  per  cent,  on  10 
kilos? 

161.  How  many  grams  of  dyestuff  would  be  required  to  give  0.05  per  cent, 
on  10  pounds  of  yarn?    For  0.75  per  cent,  on  5  pounds?     For  2\  per  cent,  on 
3  pounds? 

162.  How  much  borax  would  be  required  to  give  a  litre  of  a  solution  such 
that  10  cc.  would  be  equivalent  to  2  per  cent,  on  5  grams?     How  many  cubic 
centimeters  of  a  borax  solution  containing  50  grams  per  litre  would  be  needed 
to  give  2  per  cent,  on  5  grams? 

163.  ioo  grams  per  100  kilos  is  equivalent  to  how  many  ounces  per  100 
pounds?      10  grams  per  kilo  is  equivalent  to  how  many  grains  per  pound? 
2  ounces  per  ioo  pounds  is  equivalent  to  how  many  grams  per  ioo  kilos? 
i  ounce  53  grains  per  pound  is  equivalent  to  how  many  grams  per  kilo  ? 

164.  If  a  5-gram  sample  were  dyed  with  0.2  per  cent,  of  color,  how  much 
(in  ounces  and  grains)  would  be  needed  to  obtain  the  same  color  on  ioo  pounds 
of  material  ? 


SECTION  VII. 
APPLICATION  OF  ACID  DYES. 

Experiment  42.  Dyeing  Acid  Dyes  on  Acidified  Wool.  —  Wool 
combines  with  acids  with  considerable  affinity,  and  when  so 
treated  will  dye  with  the  acid  colors  without  any  further  addition 
of  acid  to  the  dye-bath.  Carbonized  shoddy  (recovered  wool 
fibre  treated  with  acid  for  the  purpose  of  decomposing  vegetable 
fibres),  on  this  account,  will  generally  dye  more  heavily  than 
ordinary  wool  under  the  same  conditions.  Work  a  test-skein  of 
woolen  yarn  in  a  bath  containing  300  cc.  of  water  and  10  per  cent, 
of  sulphuric  acid,  boiling  for  15  minutes.  Then  rinse  in  fresh 
water  and  squeeze.  Dye  this  skein,  together  with  one  of  ordinary 
wool,  in  a  bath  containing  300  cc.  of  water,  20  per  cent,  of  glauber- 
salt,  and  i  per  cent,  of  Formyl  Violet  10  B.  After  dyeing  wash  well 
and  dry  (102,  103).  Then  compare  the  two  skeins  for  depth  of 
color,  and  it  will  be  found  that  the  one  treated  with  acid  has.  been 
dyed  much  the  deeper  shade. 

Experiment  43.  After-treatment  of  an  Acid  Dye  with  Chrome. — 
Some  of  the  acid  dyes  on  being  treated  after  dyeing  with  a  boiling 
solution  of  chrome  (potassium  bichromate)  are  changed  into 
faster  and  deeper  colors.  The  chrome  may  act  in  two  ways;  in 
the  first  place,  it  may  combine  with  the  dyestuff  to  give  a  per- 
manent color-lake  (similar  to  the  mordant  dyes),  and  secondly, 
it  may  cause  an  oxidation  of  the  dyestuff  whereby  a  new  com- 
pound is  obtained  on  the  fibre  which  is  faster  in  color  than  the 
original  one.  Dye  two  skeins  of  woolen  yarn  in  the  usual  manner 
in  a  bath  containing  300  cc.  of  water,  10  per  cent,  of  glaubersalt, 
4  per  cent,  of  sulphuric  acid,  and  i  per  cent,  of  Cloth  Red  GA. 
After  dyeing  for  one-half  hour,  lift  the  skeins  from  the  bath  (104) 
and  add  -2  per  cent,  of  chrome.  Reenter  one  of  the  skeins,  and 
continue  boiling  for  20  minutes.  Then  wash  and  dry  (105). 

85 


86  DYEING  AND   TEXTILE  CHEMISTRY. 

Compare  the  color  of  the  two  skeins,  and  it  will  be  noticed  that 
the  chromed  one  is  deeper  in  shade.  Test  the  fastness  of  the 
dyeings  to  washing  in  the  following  manner:  Take  a  portion  of 
each  skein  and  plait  it  with  some  strands  of  white  woolen  yarn, 
and  then  scour  the  samples  so  prepared  in  a  lukewarm  dilute 
soap  solution  containing  about  5  grams  of  soap  per  litre.  Next 
wash  in  fresh  water,  and  allow  the  two  tests  (106,  107)  to  dry, 
and  compare  them  as  to  the  loss  of  color  and  as  to  the  amount  of 
color  that  bleeds  into  the  white  wool. 

Experiment  44.  Use  of  Acetic  Acid  in  Dyeing  Acid  Colors.  — 
Some  of  the  acid  dyes  tend  to  go  on  to  the  fibre  too  rapidly  if 
sulphuric  acid  is  used  in  the  bath,  owing  to  the  fact  that  the  color 
acid  is  liberated  too  rapidly  and  has  a  strong  affinity  for  the  fibre ; 
hence  uneven  dyeings  are  liable  to  result.  This  fault  may  be 
avoided  by  using  a  weak  acid,  such  as  acetic  acid,  and  not 
adding  all  of  the  acid  at  once  but  in  several  portions.  To  more 
thoroughly  exhaust  the  bath  some  sulphuric  acid  may  be  added 
towards  the  end  of  the  dyeing  operation.  Prepare  a  dye-bath 
containing  300  cc.  of  water,  20  per  cent,  of  glaubersalt,  and 

1  per  cent.  Alizarin  Lanacyl  Blue,  and  dye  a  skein  of  woolen 
yarn  as  usual  for  20  minutes,  then  lift  the  skein  (108)  and  add 

2  per  cent,  of  acetic  acid,  and  continue  the  dyeing  for  10  minutes 
(109).     Lift  the  skein  a  second  time  and  add  2  per  cent,  of 
sulphuric  acid  and  continue  dyeing  for  15  minutes.     Then  wash 
and  dry  (no). 

Experiment  45.  Use  of  a  Chromotrop  Dye.  —  This  class  of 
dyes  gives  red  or  brown  colors  when  dyed  in  an  acid  bath,  but 
the  color  so  obtained  is  of  little  importance.  When  after-treated, 
however,  with  solutions  of  metallic  salts  (such  as  chrome)  the 
color  changes  to  black  and  becomes  very  fast.  Prepare  a  bath  con- 
taining 300  cc.  of  water,  4  per  cent,  of  sulphuric  acid,  20  per  cent, 
of  glaubersalt,  and  6  per  cent,  of  Chromotrop  FB ;  dye  two  skeins 
of  woolen  yarn  in  this  bath  in  the  usual  manner  for  one-half 
hour,  then  lift  (in)  and  add  3  per  cent,  of  chrome  and  2  per  cent, 
of  sulphuric  acid,  reenter  one  of  the  skeins  and  continue  boiling 
for  20  minutes  (112). 


APPLICATION  OF  ACID   DYES.  8/ 

Experiment  46.  Use  of  Phthalein  Dyes.  —  These  dyes  are 
represented  by  the  eosins  and  related  coloring-matters.  They 
are  applied  in  neutral  or  weakly  acid  baths,  and  give  delicate 
red  and  pink  shades  which  are  characterized  by  a  peculiar  bright- 
ness and  fluorescence.  The  shades  may  also  be  made  more 
brilliant  by  dyeing  on  wool  which  has  first  been  treated  with 
alum.  Prepare  a  bath  containing  300  cc.  of  water,  10  per  cent, 
of  glaubersalt,  and  i  per  cent,  of  Eosin,  and  dye  a  skein  of  woolen 
yarn  in  the  usual  manner  (113).  Prepare  a  second  bath  con- 
taining 300  cc.  of  water,  10  per  cent,  of  glaubersalt,  5  per  cent,  of 
acetic  acid,  and  i  per  cent,  of  Eosin,  and  dye  a  skein  of  woolen 
yarn  in  the  usual  manner  (114).  Prepare  a  third  bath  containing 
300  cc.  of  water,  5  per  cent,  of  alum  and  5  per  cent,  of  tartar,  and 
5  per  cent,  of  acetic  acid;  boil  a  skein  of  woolen  yarn  in  this  bath 
for  one-half  hour,  then  lift  and  add  i  per  cent,  of  Eosin,  and 
continue  dyeing  for  20  minutes  (115).  The  Erythrosine,  Phlox- 
ine,  and  Rose  Bengale  also  belong  to  this  group  of  phthalein 
dyes.  The  tartar  is  used  in  the  bath  to  aid  in  the  decomposition 
of  the  alum. 

Experiment  47.  General  Method  of  Dyeing  Acid  Dyes  on  Cot- 
ton.— Cotton  has  no  direct  affinity  for  the  acid  colors  and  requires 
a  basic  mordant  to  combine  with  the  color-acid  of  the  dyestuff. 
Alum  is  used  at  times  for  this  purpose.  Prepare  a  bath  containing 
250  cc.  of  water,  20  per  cent,  of  alum,  20  per  cent,  of  glaubersalt, 
and  2  per  cent,  of  Water  Blue;  enter  a  skein  of  cotton  yarn  at 
140°  F.,  raise  to  180°  F.  and  keep  at  that  temperature  for  45 
minutes;  then  squeeze  and  dry  without  washing  (116).  It  will 
be  noticed  that  a  rather  concentrated  or  " short"  bath  is  employed 
and  that  even  then  the  exhaustion  is  very  imperfect.  These 
dyes  are  not  much  used  on  cotton  at  the  present  time,  except  for 
such  materials  as  curtains,  etc.,  where  bright  colors  are  desired 
which  have  good  fastness  to  light  and  where  fastness  to  washing 
is  not  demanded.  To  show  the  lack  of  fastness  to  washing  of 
this  color,  plait  a  portion  of  the  dyed  sample  with  some  strands 
of  white  cotton  yarn,  and  scour  this  test  sample  in  a  dilute  soap 
solution  (117) ;  it  will  be  found  that  the  color  will  wash  out  almost 


88  DYEING   AND    TEXTILE   CHEMISTRY. 

completely.  When  applied  to  cotton,  these  dyes  are  usually 
known  as  "alum  colors"  because  that  salt  is  used  in  the  bath. 

Experiment  48.  Dyeing  in  a  Neutral  Salt  Bath.  —  This  method 
is  generally  employed  for  the  dyeing  of  bright  pale  shades 
on  cotton  with  the  acid  dyes.  Use  a  skein  of  bleached  cotton 
yarn,  and  dye  in  a  bath  containing  250  cc.  of  water,  10  grams 
of  common-salt,  and  10  per  cent,  of  Eosin;  work  for  45  minutes 
at  a  temperature  of  140°  F.,  then  squeeze  and  dry  without  washing 
(118).  The  large  amount  of  salt  employed  helps  to  better 
exhaust  the  bath,  as  the  dyestuff  is  less  soluble  in  salt  solutions. 
The  bath,  however,  is  in  no  wise  exhausted  and  should  be 
employed  in  practice  for  a  "standing"  bath  for  the  dyeing  of 
subsequent  lots. 

Experiment  49.  Use  of  "  Blue  Mordant."  —  This  mordant  is  a 
tartrate  of  aluminium,  and  may  be  prepared  by  dissolving  22  parts 
of  aluminium  sulphate  in  45  parts  of  water,  and  then  adding  a 
solution  of  4!  parts  of  tartaric  acid  dissolved  in  20  parts  of  water, 
after  which  gradually  add  a  solution  of  6J  parts  of  soda  ash  in 
35  parts  of  water,  and  dilute  the  whole  to  175  parts  with  water. 
For  mordanting,  use  i  part  of  this  solution  to  30  parts  of  water, 
or  10  cc.  to  300  cc.  of  water.  Work  a  skein  of  cotton  yarn  in  a 
bath  containing  300  cc.  of  water,  10  cc.  of  "blue  mordant,"  and 
i  per  cent,  of  Water  Blue  6B  for  one-half  hour  at  160°  F.  Squeeze 
and  dry  without  washing  (119). 

Experiment  50.  Use  of  Sodium  Stannate  Mordant.  —  This 
salt  is  easily  decomposed  when  its  solution  is  boiled,  and  thus 
liberates  oxide  of  tin  in  the  fibre.  It  is  used  as  follows:  Steep 
a  skein  of  cotton  yarn  for  one-half  hour  in  a  bath  containing 
200  cc.  of  water  and  5  grams  of  sodium  stannate  at  180°  F. 
Remove  the  skein,  squeeze,  and  dye  in  a  bath  containing  250  cc. 
of  water  and  i  per  cent,  of  Ponceau  46  and  5  per  cent,  of  alum; 
enter  at  140°  F.,  gradually  raise  to  190°  F.,  and  dye  at  that 
temperature  for  one-half  hour.  Squeeze  and  dry  without 
washing  (120). 

Experiment  51.  Dyeing  of  Silk  with  Acid  Dyes.  —  Dye  a 
test-skein  of  silk  yarn  in  a  bath  containing  150  cc.  of  water, 


APPLICATION  OF  ACID   DYES.  89 

2  per  cent,  of  sulphuric  acid,  and  2  per  cent.  Naphthol  Yellow; 
enter  at  i2o°F.,  gradually  raise  to  the  boil,  and  dye  at  that 
temperature  for  one-half  hour,  then  wash  well  and  "  lustre  "  by 
passing  through  a  bath  containing  i  gram  of  tartaric  acid  and 
150  cc.  of  water  at  100°  F.  Squeeze  without  washing  and  dry 
(121).  Like  wool,  silk  will  also  combine  directly  with  the  acid 
colors.  Usually  a  bath  is  employed  containing  a  considerable 
amount  of  boiled-off  liquor  acidified  with  acetic  acid.  This  is 
to  prevent  as  little  loss  in  the  weight  of  the  silk  as  possible  during 
the  dyeing,  as  silk  usually  comes  to  the  dyer  still  containing  more 
or  less  of  the  silk  glue,  which  would  come  off  in  the  dye-bath  if 
there  were  not  a  considerable  amount  of  the  same  substance 
present. 

Experiment  52.  Use  of  Acetic  Acid  in  Dyeing  Silk.  —  Dye  a 
test-skein  of  silk  yarn  in  a  bath  containing  150  cc.  of  water, 
4  per  cent,  of  acetic  acid,  and  2  per  cent.  Eosin;  enter  at  120°  F., 
gradually  raise  to  the  boil,  and  dye  at  this  temperature  for  one- 
half  hour.  Then  wash  well  and  brighten  as  in  Exp.  51.  Squeeze 
and  dry  (122).  This  method  of  dyeing  is  used  where  feebly  acid 
dyes  are  employed. 

Experiment  53.  Use  of  Boiled-off  Liquor  in  Dyeing  Silk.  — 
Boiled-off  liquor  is  the  scouring  bath  left  after  the  scouring 
of  silk  with  strong  soap  solutions,  and  consists  of  the  solution 
of  soap  and  silk-glue.  Prepare  a  bath  containing  15  cc.  of  boiled- 
off  liquor  and  125  cc.  of  water,  2  per  cent,  of  Brilliant  Croceine, 
and  sufficient  sulphuric  acid  to  give  the  bath  a  decidedly  acid 
reaction  with  litmus  paper.  The  presence  of  the  silk-glue  pre- 
vents the  precipitation  of  the  soap  by  the  addition  of  the  acid. 
Dye  a  test-skein  of  silk  yarn  in  this  bath,  entering  at  100°  F.  and 
gradually  raising  to  180°  F.,  and  continue  at  that  temperature 
for  one-half  hour.  Wash  well  and  brighten  as  described  in 
Exp.  51.  Squeeze  and  dry  (123).  , 


9o 


DYEING  AND   TEXTILE  CHEMISTRY. 


NOTES. 

i.  List  of  the  Principal  Acid  Dyestuffs.  —  The  acid  dyes  to  be 
met  with  upon  the  market  at  the  present  time  include  a  very 
large  number.  This  is  further  increased  by  the  fact  that  many 
different  names  are  frequently  given  to  the  same  dyestuff  by 
different  manufacturers  and  dealers,  and  still  further  by  the  use 
of  mixed  dyes  to  produce  different  shades  and  tones.  It  would 
be  practically  impossible  to  give  a  complete  list  of  all  the  acid 
dyes  which  are  sold,  but  the  following  will  give  a  fair  idea  of  the 
principal  dyes.  They  are  roughly  classified  according  to  color. 


(a)  RED. 


Acid  Carmoisine. 
Acid  Cerise. 
Acid  Fuchsine. 
Acid  Magenta. 
Acid  Maroon. 
Acid  Red. 
Acid  Rhodamine. 
Acid  Rosamine. 
Acid  Ponceau. 
Alkali  Fast  Red. 
Amaranth. 

Amido  Naphthol  Red. 
Anisoline. 
Anthracene  Red. 
Apollo  Red. 
Archil  Substitute. 
Azo  Acid  Carmine. 
Azo  Acid  Fuchsine. 
Azo  Acid  Rubine. 
Azo  Acid  Magenta. 
Azo  Bordeaux. 
Azo  Cardinal. 
Azo  Carmine. 
Azo  Coccine. 
Azo  Cochineal. 
Azo  Crimson. 
Azo  Eosin. 
Azo  Fuchsine. 


Azo  Grenadine. 
Azo  Phloxine. 
Azo  Orseille. 
Azo  Red. 
Azo  Rubine. 
Benzyl  Red. 
Biebrich  Acid  Red. 
Biebrich  Scarlet. 
Bordeaux. 

Brilliant  Acid  Carmine. 
Brilliant  Bordeaux. 
Brilliant  Carmoisine. 
Brilliant  Cochineal. 
Brilliant  Croceine. 
Brilliant  Double  Scarlet. 
Brilliant  Fast  Red. 
Brilliant  Orseille. 
Brilliant  Ponceau. 
Brilliant  Rubine. 
Brilliant  Scarlet. 
Brilliant  Sulphon  Red. 
Cardinal. 
Cardinal  Red. 
Carmoisine. 
Cerasine. 
Chromazon  Red. 
Chromotrop. 
Chromotrop  2R. 


APPLICATION  OF  ACID  DYES. 


(a)  RED.  —  Continued. 


Clayton  Cloth  Red. 

Cloth  Red. 

Cloth  Scarlet. 

Coccine. 

Coccinine. 

Cochineal  Red. 

Cochineal  Scarlet. 

Cotton  Scarlet. 

Cresol  Red. 

Croceine. 

Croceine  Scarlet. 

Crystal  Ponceau. 

Cyanosine. 

Double  Brilliant  Scarlet. 

Double  Ponceau. 

Double  Scarlet. 

Emin  Red. 

Eosamine. 

Eosin. 

Eosin  Scarlet. 

Erythrine. 

Erythrosine. 

Fast  Acid  Eosin. 

Fast  Acid  Fuchsine. 

Fast  Acid  Phloxine. 

Fast  Bordeaux. 

Fast  Claret  Red. 

Fast  Ponceau. 

Fast  Red. 

Fast  Scarlet. 

Florida  Red. 

Guinea  Bordeaux. 

Guinea  Carmine. 

Lanafuchsine. 

Mars  Red. 

Mercerine  Wool  Red. 

Mercerine  Wool  Scarlet. 


Milling  Red. 
Milling  Scarlet. 
Naphthorubine. 
Naphthol  Red. 
Naphthol  Scarlet. 
Naphthylamine  Red, 
New  Claret. 
New  Coccine. 
New  Red. 
Orcelline. 
Orseille  Red. 
Palatine  Red. 
Palatine  Scarlet. 
Phloxine. 
Ponceau. 
Pyrotine  Red. 
Roccelline. 
Rock  Scarlet. 
Rosazeine. 
Rose  Bengale. 
Rosinduline. 
Roxamine. 
Salicine  Red. 
Scarlet. 
Silk  Red. 
Silk  Scarlet. 
Sorbine  Red. 
Sulphon  Carmine. 
Tolane  Red. 
Tyemond  Red. 
Tyemond  Scarlet. 
Victoria  Rubine. 
Victoria  Scarlet. 
Violamine. 
Wool  Red. 
Wool  Scarlet. 


DYEING  AND    TEXTILE  CHEMISTRY. 


(b)  ORANGE. 


Aniline  Orange. 
Aurantia. 
Brilliant  Orange. 
Croceine  Orange. 
Crystal  Orange. 
Gold  Orange. 
Kermesine  Orange. 
Mandarin  G. 


Milling  Orange. 
Orange  I. 
Orange  II. 
Orange  IV. 
Orange  R,  G,  etc. 
Palatine  Orange. 
Pyrotine  Orange. 
Tyemond  Orange. 


(c)  YELLOW. 


Acid  Yellow. 
Alkali  Yellow. 
Alpine  Yellow. 
Azo  Acid  Yellow. 
Azo  Flavine. 
Azo  Yellow. 
Brilliant  Yellow. 
Chinoline  Yellow. 
Ghrysoine. 
Cinereine. 
Citronine. 
Curcumine. 
Fast  Yellow. 
Fast  Light  Yellow. 
Flavaniline. 
Flavazine. 
Golden  Yellow. 
Helianthine. 
Indian  Yellow. 
Martius  Yellow. 


Mercerol  Wool  Yellow. 
Metanil  Yellow. 
Milling  Yellow. 
Naphthol  Yellow. 
Naphthol  Yellow  S. 
Naphthylamine  Yellow. 
New  Yellow. 
Persian  Yellow. 
Picric  Acid. 
Quinoline  Yellow. 
Resorcine  Yellow. 
Solid  Yellow. 
Sun  Yellow. 
Tartrazine. 
Tropaeoline. 
Tyemond  Yellow. 
Uranine. 
Victoria  Yellow. 
Wool  Yellow. 
Xanthamine. 


Acid  Green. 
Alkali  Fast  Green. 
Alizarin  Green. 
Alizarin  Cyanine  Green. 
Anthracene  Acid  Green. 
Benzyl  Green. 
Brilliant  Acid  Green. 


(d)  GREEN. 

Brilliant  Milling  Green. 
Cyanole  Green. 
Cyprus  Green. 
Diamond  Green. 
Domingo  Green. 
Eboli  Green. 
Fast  Acid  Green. 


APPLICATION  OF  ACID   DYES. 


93 


(d)  GREEN.  —  Continued. 


Fast  Green. 
Fast  Green  Bluish. 
Fast  Light  Green. 
Guinea  Green. 
Kiton  Green. 
Light  Green. 
Milling  Green. 


Acid  Peacock  Blue. 
Alizarin  Blue  SAP,  SAE. 
Alizarin  Pure  Blue. 
Alizarin  Saphirol. 
Alkali  Blue. 
Anthra  Cyanine. 
Anthracene  Blue. 
Azine  Blue. 
Azo  Acid  Blue. 
Azo  Marine  Blue. 
Bavarian  Blue. 
Benzyl  Blue. 
Biebrich  Acid  Blue. 
Blackley  Blue. 
Brilliant  Blue. 
Brilliant  Silk  Blue. 
Carmine  Blue. 
China  Blue. 
Cloth  Blue. 
Coomassie  Navy  Blue. 
Copper  Blue. 
Cotton  Blue. 
Cyanine. 
Cyanole. 
Cyprus  Blue. 
Disulphine  Blue. 
Eriochlorine. 
Eriocyanine. 
Erioglaucine. 
Fast  Acid  Blue. 
Fast  Blue. 


Naphthaline  Green. 
Naphthol  Green. 
Neptune  Green. 
Night  Green. 
Patent  Green. 
Wool  Green. 


(e)  BLUE. 


Fast  Blue  Black. 
Fast  Blue  for  Wool. 
Fast  Sky  Blue. 
Fluorescent  Blue. 
Formyl  Blue. 
Full  Blue. 
Gallanil  Indigo. 
Gallocyanine. 
Gallazin  A. 
Gentiana  Blue. 
Indigo  Blue. 
Indigo  Carmine. 
Indigo  Extract. 
Indigo  Substitute. 
Indigotine. 
Indocyanine. 
Induline. 
Intensive  Blue. 
Ketone  Blue. 
Kiton  Blue. 
Lanacyl  Blue. 
Lanacyl  Marine  Blue. 
Lazuline  Blue. 
Lyons  Blue. 
Marinol  Acid  Blue. 
Marine  Blue. 
Methane  Dark  Blue. 
Methyl  Alkali  Blue. 
Methyl  Soluble  Blue. 
Milling  Blue. 
Naphthaline  Blue. 


94  DYEING  AND    TEXTILE  CHEMISTRY. 

(e)  BLUE.  —  Continued. 

Naphthazine  Blue.  Sapphire  Blue. 

Naphthol  Blue.  Silk  Blue. 

Naphthyl  Blue.  Solid  Blue. 

Navy  Blue.  Soluble  Blue. 

New  Patent  Blue.  Spirit  Blue. 

Night  Blue.  Sulphon  Acid  Blue. 

Opal  Blue.  Thiocarmine. 

Patent  Blue.  Urania  Blue. 

Patent  Marine  Blue.  Victoria  Marine  Blue. 

Patent  Neutral  Blue.  Water  Blue. 

Peri  Wool  Blue.  Wool  Blue. 

Pure  Blue.  Wool  Marine  Blue. 

(/)  VIOLET. 

Acid  Mauve.  Formyl  Violet. 

Acid  Violet.  Guinea  Violet. 

Alkali  Violet.  Lanacyl  Violet. 

Azo  Acid  Violet.  Naphthyl  Violet. 

Benzal  Violet.  Neutral  Violet. 

Benzyl  Violet.  Red  Violet. 

Biebrich  Acid  Violet.  Regina  Violet. 

Fast  Acid  Violet.  Victoria  Violet. 

Fast  Sulphon  Violet.  Violamine. 

Fast  Violet.  Wool  Violet. 

(g)  BROWN. 

Acid  Brown.  Dark  Acid  Brown. 

Azo  Brown.  Fast  Brown. 

Bismarck  Acid  Brown.  Matron. 

Bronze  Acid  Brown.  Naphthol  Brown. 

Chestnut  Brown.  Naphthylamine  Brown. 

Chromogen.  Resorcin  Brown. 
Clayton  Wool  Brown. 

(&)  BLACK. 

Acid  Black.  Anthracene  Acid  Black. 

Alizarin  Black.  Anthracite  Black. 

Amido  Naphthol  Black.  Azo  Acid  Black. 

Aniline  Gray.  Azo  Black. 


APPLICATION  OF  ACID  DYES.  95 

(h)  BLACK.  —  Continued. 

Azo  Merino  Black.  Naphthyl  Blue  Black. 

Biebrich  Patent  Black.  Naphthylamine  Black. 

Brilliant  Black.  Nerol. 

Cashmere  Black.  New  Victoria  Black. 

Coomassie  Black.  Nigrosine. 

Copper  Black.  Palatine  Black. 

Deep  Black.  Patent  Palatine  Black. 

Domingo  Acid  Black.  Phenol  Black. 

Domingo  Azo  Black.  Phenylamine  Black. 

Domingo  Blue  Black.  Phenylene  Black. 

Domingo  Violet  Black.  Silk  Black. 

Mercerol  Wool  Black.  Sudan  Black. 

Methane  Black.  Victoria  Black. 

Naphtacyl  Black.  Wool  Black. 

Naphthaline  Acid  Black.  Wool  Deep  Black. 

Naphthol  Black.  Wool  Gray. 

SAMPLES. 

102.  Wool  not  acidified,  dyed. 

103.  Acidified  wool  dyed. 

104.  Cloth  Red  before  chroming. 

105.  Cloth  Red  after  chroming. 

106.  Scouring  test  of  unchromed  sample. 

107.  Scouring  test  of  chromed  sample. 

1 08.  Alizarin  Lanacyl  Blue  before  adding  acid. 

109.  After  addition  of  acetic  acid. 
no.  After  addition  of  sulphuric  acid, 
in.   Chromotrop  dye  before  chroming. 

112.  Chromotrop  dye  after  chroming. 

113.  Phthalein  dye  in  neutral  bath. 

114.  Phthalein  dye  in  acetic  acid  bath. 

115.  Phthalein  dye  on  wool  treated  with  alum. 

1 1 6.  Water  Blue  on  cotton  with  alum. 

117.  Scouring  test  with  Water  Blue. 

1 1 8.  Acid  dye  on  cotton  in  neutral  salt  bath. 

119.  Use  of  "blue  mordant"  on  cotton. 

120.  Use  of  sodium  stannate  mordant  on  cotton. 

121.  General  method  of  dyeing  silk  with  acid  dyes. 

122.  Dyeing  silk  in  an  acetic  acid  bath. 

123.  Dyeing  silk  with  acid  dye  in  bath  of  boiled-off  liquor. 


96  DYEING  AND   TEXTILE  CHEMISTRY. 

QUIZ  7. 

165.  Does  wool  combine  chemically  with  acids  ?    What  proof  can  you  give 
of  this  ? 

1 66.  Does  acidified  wool  react  in  the  same  manner  as  ordinary  wool  with 
acid  colors  ?    What  is  the  reason  of  this  ? 

167.  What  is  meant  by  "carbonized"  shoddy?    Why  does  this  dye  up 
differently  from  ordinary  wool  ? 

1 68.  What  is  chrome?    What  is  its  action  on  some  acid  dyes?    What  is 
the  purpose  of  the  after-treatment  with  chrome  ? 

169.  How  is  the  after-treatment  with  chrome  carried  out?    What  effect 
has  the  treatment  on  the  shade  of  Cloth  Red  ? 

170.  Does  the  treatment  with  chrome  have  any  effect  on  the  fastness  of 
Cloth  Red  to  scouring  ?     How  was  the  scouring  test  conducted  ? 

171.  Why  is  acetic  acid  sometimes  used  in  place  of  sulphuric  acid  in  the 
dyeing  of  acid  colors  ? 

172.  How  is  acetic  acid  applied  in  the  acid  dye-bath  ?    Why  is  sulphuric 
acid  often  added  towards  the  end  of  the  dyeing? 

173.  How  are  the  chromotrop  dyes  applied  ?    Explain  the  action  of  metallic 
salts  on  the  color. 

174.  What   color   does   Chromotrop   FB    give   before  chroming?    After 
chroming? 

i75-  What  is  meant  by  a  phthalein  dye?    What  characteristic  property 
do  these  dyes  possess? 

176.  In  what  three  ways  may  eosin  be  applied  to  wool?    Compare  the 
results  of  the  processes. 

177.  Of  what  chemical  character  are  the  phthalein  dyes?    Explain  the 
action  of  the  alum  on  the  dyestuff. 

178.  In  the  preparation  of  the  wool  with  alum,  what  is  the  action  of  the 
tartar? 

179.  What  other  dyes  belong  to  the  phthalein  class  ?    What  colors  are  these 
dyes? 

1 80.  How  must  cotton  be  prepared  in  order  to  dye  with  acid  colors?    What 
character  of  mordant  must  be  used  ? 

181.  What  mordant  is  mostly  used  for  dyeing  acid  colors  on  cotton  ?    How 
is  the  dyeing  operation  carried  out  ? 

182.  What  is  meant  by  a  "short"  bath?    Does  the  acid  dye-bath  with 
cotton  exhaust  well  ? 

1 83 .  Are  acid  dyes  much  used  for  cotton  dyeing  ?    On  what  classes  of  cotton 
goods  are  they  mostly  used  ? 

184.  Are  the  acid  dyes  on  cotton  fast  to  light?    To  washing?    What  was 
the  result  of  your  washing  test,  and  how  was  the  test  conducted  ? 

185.  What  is  meant  by  "alum"  colors  on  cotton,  and  why  are  they  so  called  ? 


APPLICATION  OF  ACID  DYES.  97 

1 86.  Give  the  method  of  applying  acid  dyes  to  cotton  in  a  neutral  salt  bath. 
For  what  character  of  colors  is  this  method  used  ? 

187.  Explain  the  action  of  the  salt  in  the  dye-bath  with  acid  colors  on  cotton. 
What  is  meant  by  a  "standing"  bath,  and  what  are  the  advantages  of  using 
standing  baths  in  dyeing  ? 

188.  Of  what  does  "blue  mordant"  consist?    How  is  it  prepared? 

189.  How  is  "blue  mordant"  employed  in  connection  with  acid  colors  on 
cotton  ?     How  do  the  results  obtained  by  its  use  compare  with  those  dyed  in  a 
plain  alum  bath? 

190.  What  is  the  general  method  of  dyeing  acid  colors  on  silk? 

191.  What  is  meant  by  "lustring"  or  "brightening"  silk  after  dyeing,  and 
how  is  this  done?    How  does  this  treatment  affect  the  "scroop"  of  the  silk? 

192.  Under  what  conditions  is  acetic  acid  used  in  dyeing  silk?    Why  is 
boiled-off  liquor  used  in  the  dye-bath  ? 

193.  Give  the  method  of  dyeing  acid  colors  on  silk  in  a  bath  of  boiled-off 
liquor.    At  what  temperatures  is  the  dyeing  done  ? 


SECTION   VIII. 
REPRESENTATIVE  ACID  DYES. 

Experiment  54.    Representative  Acid   Dyes  on  Wool.  —  Dye 

test-skeins  of  woolen  yarn  in  baths  containing  300  cc.  of  water, 
20  per  cent,  of  glaubersalt,  4  per  cent,  of  sulphuric  acid,  and  i  per 
cent,  respectively  of  the  following  dyestuffs: 

Naphthol  Red  EB  (Cass.)  (124).  Acid  Violet  5BF  (Metz)  (129). 

Emin  Red  (Ber.)  (125).  Patent  Blue  V  (Metz)  (130). 

Tartrazine  (K.  &  P.)  (126).  Orange  II  (S.&S.)  (131). 

Naphthol  Yellow  S  (Sch.)  (127).  Wool  Blue  26  (Ber.)  (132). 

Alizarin  Blue  SAE  (Elb.)  (128).  Acid  Green  (Elb.)  (133). 

Enter  at  140°  F.,  gradually  raise  to  the  boil,  and  continue  at  that 
temperature  for  one-half  hour;  wash  well  and  dry.  These  test- 
skeins  are  to  be  preserved  for  the  purpose  of  testing  the  colors  for 
fastness  to  various  agencies. 

Experiment  55.  Representative  Acid  Dyes  on  Cotton.  —  Dye 
test-skeins  of  cotton  yarn  in  baths  containing  200  cc.  of  water, 
20  per  cent,  of  alum,  and  50  per  cent,  of  common-salt  at  a  tempera- 
ture of  1 80°  F.  for  i  hour.  Wring  out  and  dry  without  washing. 
Preserve  the  dyed  skeins  for  the  purpose  of  testing  the  colors  for 
fastness. 

Use  10  per  cent,  of  the  following  dyestuffs: 

Brilliant  Orange  G  (Metz)   (134). 
Ponceau  4R  (Ber.)  (135). 
Rose  Bengale  (Metz)  (136). 
Methyl  Blue  (Ber.)  (137). 
Brilliant  Croceine  M  (Cass.)   (138). 
Metanil  Yellow  (Ber.)   (139). 
Erythrosine  B  (Cass.)   (140). 
Irisamine  G  (Cass.)   (141). 

98 


REPRESENTATIVE   ACID   DYES.  99 

Experiment  56.  Representative  Acid  Dyes  on  Silk.  —  Dye  test- 
skeins  of  silk  yarn  in  baths  containing  150  cc.  of  water,  15  cc.  of 
boiled-off  liquor,  and  acidify  with  sulphuric  acid.  Dye  for 
i  hour  at  180°  F.  Wash  well  and  brighten  with  tartaric  acid. 

Use  2  per  cent,  of  the  following  dyestuffs: 

Acid  Magenta  (R.H.)  (142).  Crystal  Ponceau  6R   (Cass.) 

Acid  Violet  4RS  (Metz)  (143).  (147). 

Methyl  Blue  for  silk  (Metz)  (144).  Cyanole  BB  (Cass.)  (148). 
Orange  II  (S.&S.)  (145).  Acid  Green  (Elb.)  (149). 

Lyons  Blue  (S.&S.)  (146).  Azo  Fuchsine  (Elb.)  (150). 

Silk  Black  4BF  (Ber.)  6  per  cent.  (151). 

NOTES. 

i.  Dyestuff  Manufacturers.  —  The  abbreviations  after  the 
names  of  the  dyestuffs  refer  to  the  names  of  the  manufacturers  or 
American  agents,  as  the  case  may  be.  The  principal  manufac- 
turers of  dyestuffs  with  their  American  agents  are  as  follows: 

Bad.  for  Badische  Company  (formerly  Kuttroff,  Pickhardt  &  Co.),  agents  for 
the  Badische  Anilin  und  Soda  Fabrik  (B.  A.  S.  F.)  of  Ludwigshafen, 
Germany. 

Elb.  for  Farbenfabriken  of  Elberfeld  Company,  agents  for  the  same  company 
of  Elberfeld,  Germany. 

Ber.  for  Berlin  Aniline  Works,  agents  for  the  Actien  Gesellschaft  fiir  Anilin 
Fabrikation,  of  Berlin,  Germany. 

Cass.  for  Cassella  Color  Company,  agents  for  Leopold  Cassella  &  Co.,  of 
Frankfort,  Germany. 

Metz  for  H.  A.  Metz  &  Co.,  agents  for  the  Farbwerke  Hochst,  vorms.  Meister, 
Lucius,  &  Brunig  Company,  of  Hochst,  Germany. 

Kalle  for  Kalle  &  Co.,  agents  for  the  same  company,  of  Biebrich,  Germany. 

Sykes  for  Walter  F.  Sykes  &  Co.  (formerly  Sykes  &  Street),  agents  for  Socie'te' 
Anonyme  des  Matieres  Colorantes  et  Produits  Chimiques  de  St.  Denis, 
of  France. 

Nat.  for  National  Aniline  Company  (formerly  Hartford,  Hanna  &  Schoellkopf 
Company),  of  Buffalo,  American  manufacturers  of  dyes. 

Bch.  for  Beach  &  Co.,  agents  for  British  Alizarin  Company,  England;  for 
Brooke,  Simpson,  &  Spiller,  England;  for  Farbwerke  Griesheim,  Ger- 
many; and  for  Socie'te  Chimique  des  Usines  de  Rhone,  France. 

Bd.  for  J.  A.  &  W.  Bird  Company,  agents  for  the  Clayton  Aniline  Company, 
England. 


IOO  DYEING  AND    TEXTILE  CHEMISTRY. 

Bs.  for  C.  Bischoff  &  Co.,  agents  for  Farbenfabriken  Dahl  &  Co.,  Elberfeld, 

Germany,  and  for  Farbwerk  Muhlheim,  vorms.  A.  Leonhardt   &  Co., 

Muhlheim,  Germany. 
Kip.  for  A.  Klipstein   &  Co.,  agents  for  Farbwerke  vorms.  Durand,  Huguenin 

&  Co.,  Basle,  Switzerland;  for  Gesellschaft  fiir  Chemische  Industrie,  of 

Basle,  Switzerland;  and  for  Carl  Neuhaus,  of  Elberfeld,  Germany. 
Kell.  for  John  J.  Keller  &  Co.,  agents  for  Anilin  und  Extract  Fabriken,  of 

Basle,  Switzerland. 

Lev.  for  Levinstein,  Slackle  &  Crumpsall,  England. 
Gy.  for  Geigy  Aniline  and  Extract  Company,  agents  for  the  same  company,  of 

Basle,  Switzerland. 

Gei.  for  Geisenheimer  &  Co.,  agents  for  K.  Oehler,  Offenbach,  Germany. 
RH.  for  Read  Holliday  &  Sons,  agents  for  the  same  company,  of  England. 
Ly.  for  Thomas  Leyland  &  Co.,  agents  for  Levinstein,  England. 
AD.  for  Andreykovicz    &  Dunck,  agents  for  Chemische  Fabriken,  vorms. 

Weiler-ter-Meer,  Uerdingen,  Germany. 

The  letters  after  the  names  of  dyestuffs  are  usually  private 
trade  distinctions  for  the  use  of  the  manufacturer  in  identifying 
the  color.  They  may  also  refer  to  the  particular  shade  of  the 
dyestuff,  as,  for  example,  B  stands  for  blue  shade,  R  for  a  red 
shade,  G  (gelb)  for  a  yellow  shade,  etc. 

2.  On  the  Proper  Storage  of  Dyestuffs.  —  Dyestuffs  should  be 
kept  in  a  cool  dry  room,  and  any  barrels  or  tins  which  have  been 
opened  should  be  kept  well  covered  up,  otherwise  one  color  may 
become  contaminated  by  dust  from  another  dye,  and  the  dye- 
stuffs  are  liable  to  absorb  moisture  from  the  air.     The  absorption 
of  moisture  may  cause  the  dyestuff  to  cake  together  and  become 
difficult  to  dissolve,  and  besides  the  dyestuff  will  alter  its  weight 
by  the  amount  of  moisture  absorbed.     Steam  from  the  dyehouse 
should  be  carefully  excluded  from  the  drug  room  in  which  the 
dyes  are  stored.     Dyestuffs  in  the  form  of  pastes  should  always 
be  well  stirred  up  before  weighing  out  and  should  be  kept  from 
exposure  to  the  air,  otherwise  the  water  of  the  paste  will  evaporate 
and  the  dyestuff  will  alter  very  materially  in  its  strength.     Paste 
dyes  are  usually  of  20  per  cent,  strength;  that  is,  they  contain 
20  per  cent,  of  actual  dyestuff,  the  rest  being  water. 

3.  On  the  Dissolving  of  Dyestuffs.  —  Dyes  should  be  dissolved 
by  stirring  up  with  a  sufficient  amount  of  pure  boiling  water. 


REPRESENTATIVE  ACID  DYES.  IOI 

Distilled  water  is  the  best  to  use  for  this  purpose,  but  where  this 
is  not  available,  water  from  condensed  steam  should  be  employed. 
All  dyes  should  be  well  dissolved  before  being  added  to  the 
dye-bath.  After  dissolving,  the  dye  solution  should  be  filtered 
through  a  fine  hair  sieve  or  through  a  coarse  cotton  cloth,  in  order 
to  prevent  undissolved  particles  and  lumps  from  passing  into 
the  bath.  A  few  colors  like  Auramine  should  not  be  dissolved 
in  boiling  water,  as  the  color  is  partially  decomposed ;  such  colors 
should  be  dissolved  at  about  160°  to  180°  F.  The  amount  of 
water  required  for  dissolving  dyes  varies  greatly  with  the  different 
colors;  250  parts  of  water  to  i  part  of  dye  will  be  sufficient 
for  even  such  dyes  as  are  soluble  with  difficulty;  for  readily 
soluble  dyes  from  10  to  50  parts  of  water  will  be  sufficient. 
In  general  it  may  be  said  that  for  difficultly  soluble  dyes  one- 
half  pound  may  be  dissolved  in  10  gallons  of  water,  and  for 
ordinary  dyes  about  2  pounds  may  be  dissolved  in  10  gallons  of 
water.  Hard  water  should  not  be  employed  for  the  solution  of 
dyestuffs,  as  many  dyes  are  precipitated  or  otherwise  affected 
by  the  metallic  salts  present  in  such  water;  this  is  especially  true 
of  the  basic  dyes.  Where  it  is  necessary  to  use  hard  water, 
it  should  be  corrected  by  the  addition  of  a  small  amount 
of  acetic  acid,  or  with  soda,  depending  on  the  nature  of  the 
dyestuff.  For  basic  dyes  acetic  acid  should  be  used,  sufficient 
being  added  to  the  water  to  give  it  an  acid  reaction  with  litmus 
paper.  Any  acid  dyes  which  may  be  affected  by  the  hardness 
of  the  water  should  also  be  dissolved  with  the  aid  of  acetic  acid. 
For  Water  Blue,  Alkali  JBlue,  or  Acid  Violet,  acid  should  not  be 
used,  but  a  little  soda  or  borax  should  be  added  to  the  water. 
The  same  is  also  true  for  the  general  class  of  phthalein  dyes,  in 
which  case  the  hard  water  should  be  boiled  up  with  a  little  soda 
ash,  allowed  to  settle  and  used  for  dissolving  the  dyestuff.  In 
dissolving  substantive  dyes,  hard  water  should  also  be  corrected 
with  the  addition  of  a  small  amount  of  soda.  The  precipitation 
of  dyestuff  from  standing  baths  is  generally  caused  by  the  use  of 
impure  water  or  by  the  gradual  accumulation  of  too  much  salt 
in  the  bath. 


102  DYEING  AND   TEXTILE  CHEMISTRY. 

4.  Apparatus  for  Dyeing.  —  Yarn  is  mostly  dyed  in  suitable 
wooden  vats,  the  skeins  being  suspended  in  the  vats  from  wooden 
sticks.     Many  dyes  are  more  or  less  sensitive  to  the  action  of 
metals,  though  in  many  cases  bronze  or  copper  surfaces  may  be 
in  contact  with  the  dye-vat  without  injury  to  the  color.     Silk  is 
frequently  dyed  in  copper  vats.     The  sensitiveness  of  most  dyes 
to  copper  may  be  avoided  by  the  placing  of  strips  of  zinc  in  the 
vat  or  by  the  addition  of  ammonium  sulphocyanide.     Yarn  may 
also  be  dyed  on  machines,  where  the  hanks  are  turned  mechani- 
cally.    Loose  wool  is  frequently  dyed  by  poleing  in  large  round 
copper  vats;  it  may  also  be  dyed  in  rotating  machines.     Cloth  is 
generally  dyed  in  vats,  being  turned  by  means  of  a  revolving 
winch;  or  it  may  be  dyed  on  a  jigger,  consisting  of  two  sets  of 
rollers  which  roll  the  cloth  on  and  off  through  the  dye  liquor. 
Warps  are  also  dyed  by  machines.     Yarn  may  also  be  dyed  in 
cops  by  means  of  suitable  machines  so  devised  as  to  force  the 
dye  liquor  through  the  cop  by  pressure  or  suction. 

5.  Influence  of  the  Water  Employed  in  Dyeing.  —  Water  as 
employed  in  the  dyehouse  for  the  preparation  of  vats  and  the 
solution  of   the    dyestuffs    and  various    chemicals    is  generally 
obtained  either  from  a  river  supply  or  from  a  well  or  spring. 
Rain-water  is  sometimes  collected  and  employed  for  purposes 
where  a  very  pure  article  is  desired,  such  as  for  the  solution  of 
dyestuffs,  etc.;  it  is  usually  not  available  in  sufficient  quantities 
nor  regular  enough  in  its  supply  to  be  serviceable  for  the  prepara- 
tion of  dye-vats.     Rain-water  is  considered  as  the  purest  form 
of  natural  water.     Well  and  spring  water  are  derived  from  rain- 
water which  has  passed  through  the  surface  of  the  earth  until  it 
has  reached  an  impervious  layer  which  causes  it  to  collect  in 
subterranean  reservoirs  from  which  it  may  be  pumped  as  well- 
water,  or  it  may  flow  underground  until  it  eventually  reappears 
at  the  surface  as  a  spring.     Such  water  usually  contains  various 
metallic  salts  in  solution  and  generally  has  but  little  insoluble 
matter  in  suspension.      The  exact  nature  and  amount  of  the 
dissolved  substances  will  naturally  vary  considerably  with  the 
character  of  the  soil  and  rock  through  which  the  water  has 


REPRESENTATIVE  ACID   DYES.  1 03 

passed.  Some  rocks,  like  granite  and  gneiss,  are  very  insol- 
uble, and  water  percolating  through  these  may  be  quite  free 
from  dissolved  impurities,  and  springs  or  wells  from  such  a 
source  may  be  quite  "  soft."  If  the  water,  however,  in  its  perco- 
lation through  the  soil  passes  through  strata  of  limestone,  chalk, 
sandstone,  etc.,  some  mineral  compounds  pass  into  solution,  espe- 
cially salts  of  magnesia  and  lime.  Such  a  water  is  termed  "  hard." 
Iron  compounds  form  a  common  constituent  of  soils  and  rocks, 
and  consequently  water  that  passes  through  such  will  be  liable  to 
contamination  with  iron;  this  will  be  more  especially  the  case  if  at 
the  same  time  it  is  in  contact  with  decaying  vegetable  matter,  as 
the  latter  furnishes  certain  organic  acids  which  exert  a  strong 
solvent  action  on  the  iron  compounds.  Water  containing  a 
marked  content  of  iron  is  termed  "  chalybeate  "  or  "  ferruginous." 

River-water  consists  largely  of  surface-water,  that  is,  rain-water 
which  drains  directly  from  the  surface  of  the  soil  without  perco- 
lating through  the  ground  to  any  extent;  besides  this,  river-water 
also  contains  well-  or  spring-water  feeding  into  it  from  small 
streams,  etc.,  having  their  origin  in  springs.  The  surface-water 
draining  into  a  river  is  liable  to  bring  into  it  a  large  amount  of 
suspended  matter,  though  not  so  much  dissolved  matter.  The 
nature  and  extent  of  this  suspended  matter  will,  of  course,  vary 
largely  with  the  season  of  the  year  and  the  character  of  the 
environments.  From  this  it  may  be  seen  that  river-water  will, 
as  a  rule,  contain  more  suspended  matter  and  less  dissolved 
matter  than  well-water.  The  suspended  matter  is  comparatively 
easily  removed,  however,  whereas  the  dissolved  substances  may 
give  rise  to  considerable  trouble. 

The  influence  of  the  impurities  in  water  on  the  dyeing  opera- 
tions will  depend  very  largely  on  the  character  of  the  dyestuffs 
employed.  Hard  water  containing  lime  and  magnesia  com- 
pounds, as  a  rule,  does  not  interfere  with  the  dyeing  of  colors  in 
an  acid  bath,  as  the  addition  of  the  acid  prevents  any  precipita- 
tion of  the  coloring-matter  by  the  metallic  salt.  In  certain  cases 
the  tone  of  the  resulting  color-lake  may  be  somewhat  modified 
by  the  presence  of  the  mineral  salts,  but  such  is  very  rarely  the 


104  DYEING   AND    TEXTILE   CHEMISTRY. 

case.  The  presence  of  iron,  however,  even  in  very  slight  quan- 
tities, in  the  water,  may  cause  a  considerable  alteration  in  the 
color,  usually  dulling  and  darkening  it.  With  the  general  class 
of  basic  dyes  hard  water  cannot  be  employed  without  suitable 
correction  by  the  addition  of  acetic  acid.  The  basic  dyes  form 
insoluble  precipitates  with  lime  and  magnesia  compounds  which 
will  result  in  a  large  loss  of  coloring-matter  and  also  faulty  and 
streaky  dyeing  by  reason  of  the  sticky  precipitate  of  coloring- 
matter  becoming  smeared  on  the  material  being  dyed.  The 
presence  of  iron  in  the  water  is  also  very  deleterious  in  using  basic 
dyes.  With  the  class  of  substantive  colors  the  influence  of  hard 
water  varies  largely  with  the  particular  dyestuff,  in  some  cases 
causing  precipitation  and  in  others  not.  As  a  general  rule, 
however,  it  may  be  taken  that  hard  water  is  deleterious  with  this 
class  of  dyes,  and  should  be  corrected  by  the  addition  of  a  suitable 
amount  of  soda  ash  in  order  to  precipitate  all  the  lime  and  magne- 
sia compounds  which  may  be  in  solution.  The  presence  of  iron 
is  also  bad,  as  it  causes  a  discoloration  of  the  dyestuff.  With 
mordant  dyes  the  use  of  hard  water,  if  it  does  not  contain  any 
iron,  is  considered  beneficial,  as  the  lime  present  produces  a  better 
color-lake;  in  fact,  unless  the  water  is  sufficiently  hard,  a  soluble 
salt  of  lime  is  usually  added  in  the  dyeing  of  most  alizarin  colors. 
In  certain  cases  where  a  dulled  or  " saddened"  effect  is  desired, 
the  presence  of  iron  may  be  beneficial. 

In  mordanting  operations,  such  as  in  the  use  of  metallic  salts 
on  wool  or  silk,  hard  water  may  be  used  with  impunity  provided 
it  does  not  contain  any  iron,  which  will  result  in  the  dulling  of 
the  eventual  color-lake.  In  mordanting  cotton  with  tannic  acid, 
the  use  of  hard  water  may  be  considered  as  somewhat  beneficial, 
if  anything,  as  it  leads  to  a  better  fixation  of  the  tannin  mordant. 

In  bleaching  operations  on  cotton,  where  chloride  of  lime  or 
acids  or  caustic  soda  may  be  employed,  the  use  of  hard  water  is 
not  injurious;  though  it  should  not  be  contaminated  with  iron. 
In  the  bleaching  of  wool  with  solutions  of  sodium  bisulphite, 
hard  water  may  also  be  employed.  In  all  operations  of  scouring 
or  bleaching  where  soap  solutions  are  employed  hard  water  should 
not  be  used,  as  the  soap  forms  a  highly  insoluble  and  sticky  precip- 


REPRESENTATIVE   ACID   DYES.  10$ 

itate  with  the  mineral  salts  present  in  the  water,  causing  thereby 
great  loss  of  soap  and  the  liability  of  serious  faults  in  the  textiles 
due  to  the  precipitate  of  soap  becoming  incorporated  with  the 
fabrics.  One  part  of  lime  present  in  hard  water  will  precipitate 
about  sixteen  parts  of  ordinary  soap. 

When  hard  water  is  employed  for  the  washing  of  fabrics, 
whether  after  scouring,  dyeing,  or  bleaching,  it  may  give  rise  to 
certain  faults  known  as  "  lists"  by  reason  of  draining  and  evap- 
orating unevenly  of  the  hard  water  from  the  goods,  thus  leaving 
deposited  in  the  material  the  dissolved  mineral  matter.  Hard 
water,  in  fact,  is  probably  more  injurious  in  this  connection  than 
in  most  of  the  other  operations  of  dyeing. 

SAMPLES. 

124.  Naphthol  Red  EB  on  wool. 

125.  Emin  Red  on  wool. 

126.  Tartrazine  on  wool. 

127.  Naphthol  Yellow  S  on  wool. 

128.  Alizarin  Blue  SAE  on  wool. 

129.  Acid  Violet  5BF  on  wool. 

130.  Patent  Blue  V  on  wool. 

131.  Orange  II  on  wool. 

132.  Wool  Blue  26  on  wool. 

133.  Acid  Green  on  wool. 

134.  Brilliant  Orange  G  on  cotton. 

135.  Ponceau  4R  on  cotton. 

136.  Rose  Bengale  on  cotton. 

137.  Methyl  Blue  on  cotton. 

138.  Brilliant  Croceine  M  on  cotton. 

139.  Metanil  Yellow  on  cotton. 

140.  Erythrosine  B  on  cotton. 

141.  Irisamine  G  on  cotton. 

142.  Acid  Magenta  on  silk. 

143.  Acid  Violet  4RS  on  silk. 

144.  Methyl  Blue  for  silk  on  silk. 

145.  Orange  II  on  silk. 

146.  Lyons  Blue  on  silk. 

147.  Crystal  Ponceau  6R  on  silk. 

148.  Cyanole  BB  on  silk. 

149.  Acid  Green  on  silk. 

150.  Azo  Fuchsine  on  silk. 

151.  Silk  Black  4BF  on  silk. 


106  DYEING  AND    TEXTILE  CHEMISTRY. 

QUIZ  8. 

194.  Name  three  red  acid  dyes,  and  compare  the  character  of  the  colors 
they  give. 

195.  What  color  does  Tartrazine  give  on  wool  ?    Cyanole  on  silk  ?    Brilliant 
Croceine  is  of  what  color? 

196.  What  colors  do  Erythrosine  and  Irisamine  give  on  cotton?    What 
peculiarity  is  to  be  noticed  in  connection  with  these  colors? 

197.  What  do  the  letters  after  the  names  of  dyestuffs  represent?    What 
would  be  the  difference  between  Acid  Violet  4R  and  Acid  Violet  2R  ?    Acid 
Green  B  and  Acid  Green  G  ? 

198.  Name  some  of  the  more  important  dyestuff  factories  with  the  names 
of  their  agencies  in  the  United  States. 

199.  What  agencies  do  the  following  abbreviations  represent,  and  of  what 
foreign  factories  are  they  the  agents:    Bad.,  Elb.,  Ber.,  Cass.,  Metz,  Kip., 
RH.,  Bs.? 

200.  What  precautions  should  be  taken  in  the  storage  of  dyestuffs  in  the 
mill? 

201.  How  much  actual  dyestuff  do  paste  dyes  usually  contain?    What 
precautions  should  be  taken  in  the  preservation  and  use  of  these  colors  ? 

202.  What  is  the  method  recommended  in  general  for  the  dissolving  of 
dyestuffs  ?     Should  the  solid  coloring-matter  be  added  to  the  dye-bath  directly  ? 
Explain  why. 

203.  Can  all  dyestuffs  be  dissolved  in  boiling  water  without  injury  ?     Name 
some  of  these  which  cannot. 

204.  For  difficultly  soluble  dyes  how  much  water  will  be  required  for  the 
solution  of  one  part  of  dyestuff  ?     How  much  for  readily  soluble  dyes  ?    About 
how  much  dyestuff  can  be  dissolved  in  10  gallons  of  water? 

205.  Why  is  it  unsafe  to  use  hard  water  in  the  dissolving  of  dyestuffs? 
What  class  of  dyes  are  especially  sensitive  to  hard  water? 

206.  If  hard  water  has  to  be  employed  for  dissolving  basic  dyes,  how 
should  it  be  corrected?    How  are  acid  dyes  dissolved  in  hard  water? 

207.  How  should  hard  water  be  treated  for  the  solution  of  Water  Blue, 
Alkali  Blue,  and  Acid  Violet?     For  the  phthalein  dyestuffs?    For  the  sub- 
stantive dyestuffs? 

208.  What  two  causes  may  lead  to  the  precipitation  of  the  dyestuff  in  stand- 
ing baths  ? 

209.  How  is  yarn  mostly  handled  in  dyeing?    What  character  of  vat  is 
employed  ?    What  metals  only  should  be  present  in  the  dye- vat  ? 

210.  How  may  the  sensitiveness  of  most  dyes  to  copper  be  avoided,  if  it  is 
necessary  to  have  this  metal  in  the  vat  ? 

211.  Describe  the  general  forms  of  machines  employed  for  the  dyeing  of 
yarn.    What  advantages  do  machines  possess  over  hand  dyeing? 


REPRESENTATIVE  ACID   DYES.  IO/ 

212.  In  what  manner  is  loose  wool  or  cotton  dyed?     Describe  a  form  of 
machine  for  loose  stock  dyeing. 

213.  Describe  the  method  employed  for  dyeing  cloth.     What  is  a  "winch," 
a  "jigger"? 

214.  What  are  "warps"?     How  is  warp  dyeing  carried  out? 

215.  What  is  meant  by  a  "cop"?     Describe  the  principle  of  a  cop-dyeing 
machine.    'May  other  forms  of  material  besides  cops  be  dyed  in  similar 
machines  ? 

216.  If  75  kilos  of  wool  are  to  be  dyed  with  0.08  per  cent,  of  dyestuff,  how 
many  grams  of  coloring-matter  would  be  required  ?     If  100  pounds  are  to  be 
dyed  with  the  same  percentage,  how  many  ounces  and  grains  of  dyestuff  would 
be  necessary? 

217.  250  grams  per  100  kilos  is  how  many  ounces  and  grains  per  100 
pounds  ? 

218.  If  10  pounds  of  goods  are  to  be  dyed  with  £  per  cent,  of  dyestuff, 
how  many  grains  of  color  would  be  necessary  ?    What  volume  of  dye  solution 
containing  8  ounces  of  color  per  gallon  would  be  required  (in  pints,  gills,  and 
noggins)  ? 

219.  Suppose  5-gram  skeins  of  wool  are  dyed  in  tests  using  dye  solutions 
containing  i  gram  per  litre;  what  percentage  of  color  would  i  cc.  represent? 
A  color  obtained  with  20  cc.  of  the  test  solution  would  be  equivalent  to  how 
many  ounces  arid  grains  of  dyestuff  on  100  pounds  of  goods? 


SECTION  IX. 
TESTING  THE  FASTNESS  OF  COLORS. 

Experiment  57.  Fastness  to  Light.  —  For  this  test  (and  those 
succeeding)  use  five  of  the  skeins  dyed  in  the  preceding  section. 
Cut  off  a  sample  of  the  dyed  skein  about  three  inches  in  length 
and  place  it  in  an  exposure  board,  arranging  it  in  such  a  man- 
ner that  one-half  of  the  sample  is  exposed  to  the  light,  while  the 
other  half  is  protected.  Hang  the  exposure  board  on  the  inside 
of  a  window  facing  the  south  in  order  to  obtain  as  much  sunlight 
as  possible.  Allow  the  exposure  to  continue  for  one  week,  at  the 
end  of  which  time  examine  the  sample  for  fading.  If  the  color 
shows  any  perceptible  alteration,  it  must  be  considered  as  not  fast 
to  light.  If  no  fading  is  observed,  the  exposure  should  be  con- 
tinued for  three  weeks  more.  The  sample  is  now  examined  a 
second  time,  and  if  any  fading  is  apparent,  the  sample  is  removed 
and  classified  as  moderately  fast.  If  no  fading  is  apparent  the 
sample  may  be  classified  as  quite  fast  to  light  (152,  153,  154,  155, 
156).  The  degrees  of  fastness  to  light  may  also  be  classified 
numerically  as  follows: 

1.  Not  faded  in  four  weeks'  exposure. 

2.  Not  faded  in  one  week's  exposure. 

3.  Faded  by  one  week's  exposure. 

Experiment  58.  Fastness  to  Washing.  —  This  is  to  represent 
the  fastness  of  the  color  to  scouring  with  soap.  Take  5  or  6 
strands  of  the  dyed  yarn  to  be  tested  and  plait  it  with  a  similar 
amount  of  white  woolen  and  white  cotton  strands,  so  as  to  make 
up  a  small  test  sample  about  4  inches  in  length.  This  sample  is 
then  steeped  in  a  soap  solution  containing  5  grams  of  soap  per 
litre.  About  50  cc.  of  the  solution  will  be  required  for  each  test, 
and  not  more  than  one  sample  should  be  scoured  in  the  same 
liquor.  Have  the  temperature  of  the  soap  solution  at  140°  F., 

108 


TESTING   THE  FASTNESS  OF  COLORS.  1 09 

and  wash  the  sample  thoroughly  by  rubbing  with  the  hands  in 
the  same  manner  as  if  the  sample  were  dirty  and  you  were  trying 
to  clean  it.  Use  every  precaution  of  cleanliness  in  order  to  prevent 
the  sample  from  becoming  stained  with  any  other  color.  Then 
wash  well  in  fresh  warm  water,  and  dry  (157,  158,  159,  160,  161). 
Note  if  this  treatment  has  caused  the  color  to  bleed  into  either  the 
white  wool  or  cotton  with  which  the  colored  yarn  is  plaited,  also 
if  any  of  the  color  runs  into  the  soap  liquor,  and  after  drying 
compare  the  sample  with  the  original  color  and  note  if  it  has 
undergone  any  alteration. 

Experiment  59.  Fastness  to  Fulling  or  Milling.  —  Plait  together 
a  small  test  sample  about  4  inches  in  length,  using  several  strands 
of  the  dyed  yarn  and  some  strands  of  white  woolen  yarn.  Work 
the  sample  so  prepared  in  about  50  cc.  of  a  solution  containing 
5  grams  of  soap  and  2  grams  of  soda  ash  per  litre  at  a  temperature 
of  140°  F.  Rub  the  sample  vigorously  between  the  hands  or 
between  two  pieces  of  wood  in  order  to  felt  the  fibres  together  and 
so  imitate  the  action  of  fulling.  After  the  fibres  have  been  well 
felted  together,  wash  the  sample  in  fresh  warm  water,  and  dry 
(162,  163,  164,  165,  166).  Note  if  the  color  has  bled  into  the 
white  wool  or  into  the  soap  liquor;  also  compare  the  tested  sample 
with  the  original  color  and  note  if  it  has  undergone  any  alteration. 
The  fulling  test  is  only  applicable  to  dyeings  on  wool. 

Experiment  60.  Fastness  to  Water.  —  This  test  is  more 
especially  applied  to  dyeings  on  silk  and  cotton  yarns,  and  is 
to  represent  particularly  fastness  to  rain.  Plait  together  a  small 
test  sample  about  4  inches  in  length,  using  strands  of  the  dyed 
yarn  with  similar  amounts  of  white  silk  and  white  cotton  yarns. 
Steep  this  sample  in  distilled  water  for  12  hours  (over-night),  then 
squeeze  out  and  dry  (167,  168,  169,  170,  171).  Note  if  the  color 
has  bled  into  either  of  the  white  yarns  or  into  the  steeping  water. 

Experiment  61.  Fastness  to  Perspiration.  —  This  is  required 
of  all  clothing  material  intended  for  wear  next  to  the  skin;  also 
for  materials  for  making  horse-blankets,  etc.  The  action  of 
perspiration  is  an  acid  one,  and  is  said  to  be  best  represented 
chemically  by  the  action  of  acetic  or  lactic  acid  on  the  color. 


110  DYEING  AND    TEXTILE  CHEMISTRY. 

Plait  a  few  strands  of  the  dyed  yarn  with  strands  of  white  wool 
and  cotton  yarns  in  the  usual  manner,  and  steep  for  i  hour  in 
about  50  cc.  of  a  solution  containing  100  cc.  of  lactic  acid  (22  per 
cent.)  per  litre  at  the  ordinary  temperature.  Then  squeeze,  wash 
and  dry  (172,  173,  174,  175,  176).  Note  if  the  color  has  bled  into 
either  of  the  white  yarns  or  if  the  color  has  suffered  any  change 
from  the  original. 

Experiment  62.  Fastness  to  Carbonizing.  —  The  carbonizing 
process  is  the  treatment  of  woolen  material  with  acid  and  then 
drying  for  the  purpose  of  decomposing  any  vegetable  matter 
present.  It  is  especially  used  in  connection  with  shoddy,  though 
it  is  also  at  times  employed  on  woolen  piece-goods  to  remove 
specks  of  vegetable  matter  in  the  finished  cloth.  Take  a  small 
sample  of  the  dyed  woolen  skein  and  steep  it  for  15  minutes  in  a 
solution  of  sulphuric  acid  at  4°  Tw.  and  at  a  temperature  of 
140°  F.  Squeeze,  and  dry  without  washing,  then  wash  well  and 
dry  again  (177,  178,  179,  180,  181).  Note  if  the  color  has  under- 
gone any  alteration  by  this  treatment.  This  test  is  only  applicable 
to  dyed  woolen  materials. 

Experiment  63.  Fastness  to  Cross-Dyeing.  —  By  cross-dyeing 
is  meant  the  dyeing  of  pieces  containing  white  wool  woven  with 
dyed  cotton  yarn;  the  wool  being  dyed  in  a  boiling  acid  bath,  the 
dyed  cotton  must  not  be  changed  by  the  process.  Make  a  small 
plaited  sample  of  strands  of  the  dyed  cotton  yarn  with  strands  of 
white  woolen  yarn  and  boil  the  sample  so  prepared  for  15  minutes 
in  about  50  cc.  of  a  solution  containing  i  cc.  of  concentrated  sul- 
phuric acid  and  2  grams  of  glaubersalt  per  litre;  wash  well,  and 
dry  (182,  183,  184,  185,  186).  Note  if  the  color  has  undergone 
any  alteration  or  if  it  has  bled  into  the  white  yarn.  This  test  is 
applied  only  to  cotton  dyeings. 

Experiment  64.  Fastness  to  Stoving.  —  Sometimes  it  is  neces- 
sary to  bleach  woolen  pieces  containing  white  and  colored  yarns 
woven  together  in  order  to  clear  up  the  white  yarns.  This 
bleaching  is  done  with  sulphur  dioxide  (fumes  from  burning 
sulphur)  as  a  rule,  and  the  process  is  known  as  "stoving."  Take 
a  small  sample  of  the  dyed  woolen  yarn,  moisten  with  water,  and 


TESTING   THE  FASTNESS   OF   COLORS.  Ill 

hang  it  for  6  hours  in  a  closed  compartment  containing  sulphur- 
ous acid  gas.  Note  if  the  color  has  undergone  any  alteration 
(187,  188,  189,  190,  191).  This  test  is  applied  only  to  dyed 
woolen  materials. 

Experiment  65.  Fastness  to  Chloring.  —  Cotton  pieces  con- 
taining white  and  dyed  yarns  woven  together  sometimes  require 
the  bleaching  of  the  white  after  being  woven.  Towelling  with 
colored  borders  is  a  good  example  of  this  class  of  material.  The 
dyed  colors  must  therefore  stand  a  treatment  with  chloride  of 
lime  solution,  and  this  is  known  as  "chloring."  Take  a  sample 
of  the  dyed  cotton  skein  and  steep  for  one-half  hour  in  a  cold 
solution  of  chloride  of  lime  at  J°  Tw.,  rinse  off  and  pass  through 
water  slightly  acidulated  with  sulphuric  acid.  Finally  wash  well 
and  dry  (192,  193,  194,  195,  196).  Note  if  this  treatment  has 
caused  any  change  in  the  color. 

Experiment  66.  Fastness  to  Crocking  or  Rubbing.  —  By  this  is 
meant  that  the  dyed  material  should  not  stain  white  cloth  when 
rubbed  against  it.  Well-dyed  material  should  seldom  show  this 
defect,  although  plush  or  pile  fabrics  sometimes  rub  considerably. 
If  the  washing  of  the  material  after  dyeing  has  not  been  sufficiently 
thorough,  so  as  to  remove  all  particles  of  unfixed  dyestuff,  the 
color  afterwards  is  liable  to  rub.  This  fastness  is  applicable  to 
all  classes  of  dyeing.  Carry  out  the  test  by  rubbing  a  dry  sample 
of  the  dyed  yarn  vigorously  on  a  piece  of  white  calico  and  noting 
if  it  causes  any  smut  on  the  white  cloth  (197,  198,  199,  200,  201). 

The  foregoing  .tests  for  fastness  of  dyed  colors  represent  the 
principal  requirements  to  be  ordinarily  met  with.  A  careful 
study  of  the  results  of  these  tests  will  serve  to  show  that  fastness 
to  any  test,  as  well  as  the  degree  of  that  fastness,  is  not  neces- 
sarily determined  by  the  general  class  to  which  a  dyestuff  belongs, 
but  is  rather  a  particular  property  of  the  individual  dyestuff. 
Furthermore,  it  is  to  be  borne  in  mind  that  the  requirements  for 
fastness  of  colors  are  largely  to  be  determined  by  the  particular 
use  to  which  the  dyed  material  is  to  be  put,  and  an  intelligent 
discrimination  in  the  selection  of  dyes  to  be  used  should  be  made 
with  this  in  view.  A  more  extensive  discussion  of  the  fastness  of 


112 


DYEING  AND    TEXTILE  CHEMISTRY. 


dyed  colors  on  various  materials  will  be  taken  up  in  a  succeed- 
ing section,  after  the  various  methods  of  dyeing  have  been  more 
thoroughly  studied. 

Tabulation  of  Results  of  Tests. 

Make  records  of  the  results  of  the  various  tests  in  the  following 
manner,  employing  five  different  samples  for  the  respective  tests 
such  as  have  been  dyed  in  the  previous  section.  The  tested 
samples  should  be  preserved  in  the  student's  sample  book  for 
future  reference. 

FASTNESS    TO    LIGHT. 


No. 

Dyestuff. 

Fibre. 

Fading  ob- 
served in 

Fastness. 

One 
week. 

Four 
weeks. 

I52 
153 
154 
155 
156 

FASTNESS    TO    WASHING. 


Nn 

"RiKrf* 

Stains. 

Soap 
liquor. 

White 
wool. 

White 
cotton. 

1*7 

1*8 

JCQ 

1  60 

161 

TESTING   THE  FASTNESS  OF  COLORS. 
FASTNESS    TO    FULLING. 


No. 

DyestufL 

Fibre. 

Stains. 

Change  in 
color. 

Soap 
liquor. 

White 
wool. 

162 
163 
164 

1  66 

FASTNESS    TO    WATER. 

No. 

Dyestuff. 

Pibre. 

Stains. 

White 
cotton. 

White 
silk. 

Water. 

167 
1  68 
169 

170 
171 

• 

FASTNESS    TO    PERSPIRATION. 

No. 

Dyestuff. 

Fibre. 

Stains. 

Change  in 
color. 

White 
wool. 

White 
cotton. 

172 

173 

174 

175 
I76 

DYEING  AND    TEXTILE  CHEMISTRY. 


FASTNESS   TO    CARBONIZING. 


No. 


Dyestuff. 


Alteration  in  color. 


177 
I78 
179 
1 80 
181 

FASTNESS    TO    CROSS-DYEING. 
No.  Dyestuff.  Alteration  in  color.       Bleeding  into  white. 

182 

I83 
184 

185 
186 

FASTNESS    TO    STOVING. 
No.  Dyestuff.  Alteration  in  color. 

I87 
1 88 
189 
190 
191 


TESTING   THE  FASTNESS  OF  COLORS. 
FASTNESS    TO    CHLORING. 


No. 

Dyes  tuff. 

Alteration  in  color. 

IQ2 

IO3 

IQ4. 

IQC 

106 

FASTNESS    TO    CROCKING. 

No. 

Dyestuff. 

Fibre.                     Color  rubbing  on  white. 

107 

108 

TQQ 

2OO 

2OI 

SAMPLES. 

152-156. 

Tests 

for 

fastness  to  light. 

I57-I6I. 

Tests 

for 

fastness  to  washing. 

l62-l66. 

Tests 

for 

fastness  to  fulling. 

I67-I7I. 

Tests 

for 

fastness  to  water. 

172-176. 

Tests 

for 

fastness  to  perspiration. 

177-lSl. 

Tests 

for 

fastness  to  carbonizing. 

I82-I86. 

Tests 

for  fastness  to  cross-dyeing. 

I87-I9I. 

Tests 

for 

fastness  to  stoving. 

192-196. 

Tests 

for 

fastness  to  chloring. 

197-201. 

Tests 

for 

fastness  to  crocking. 

QUIZ  9. 

220.  Describe  the  method  employed  for  the  testing  of  the  fastness  of  dyed 
colors  to  light.     What  standards  of  fastness  are  adopted  ? 

221.  Why  should  a  southern  exposure  be  given  when  testing  samples  for 
fastness  to  light?    Why  should  the  samples  not  be  exposed  to  the  outside 
atmosphere  ? 


Il6  DYEING  AND    TEXTILE  CHEMISTRY. 

222.  Is  there  any  dyestuff  of  organic  nature  absolutely  fast  to  light  ?     Can 
you  explain  in  any  manner  why  light  causes  the  fading  of  colors?    Would 
colors  fade  under  red  light,  and  why  ? 

223.  What  classes  of  goods  require  fastness  to  light  more  than  others? 
Would  fancy  silks  for  ladies'  wear  require  especial  fastness  to  light,  and  why  ? 

224.  How  would  you  test  a  dyed  color  in  order  to  obtain  its  fastness  to 
washing  or  scouring  ?    What  is  the  purpose  of  twisting  white  wool  and  cotton 
with  the  sample  ? 

225.  What  is  the  strength  of  the  soap  solution  employed  for  the  scouring 
test,  and  at  what  temperature  is  the  test  conducted  ? 

226.  What  character  of  dyeings  require  especial  fastness  to  washing?    Are 
dyeings  on  silk  required  to  be  particularly  fast  to  washing? 

227.  Why  must  dyeings  on  loose  wool  or  loose  cotton  be  very  fast  to  scour- 
ing?   Explain  why  dyeings  on  weaving  yarns  should  be  fast  to  scouring. 

228.  What  defects  in  the  dyeing  process  may  lead  to  poor  fastness  to  wash- 
ing of  colors  which  would  otherwise  be  fast  ? 

229.  What  is  meant  by  fulling  or  milling ?    Explain  briefly  how  the  process 
is  carried  out.     Why  has  fulling  a  more  severe  action  on  the  color  than  scouring  ? 

230.  Give  the  method  for  testing  the  fastness  of  a  dyed  color  to  fulling. 

231.  Are  cotton  and  silk  materials  fulled?    Explain  why  woolen  materials 
felt  together  in  fulling. 

232.  What  classes  of  woolen  materials  are  usually  fulled?    Why  should 
dyeings  on  loose  wool  be  fast  to  fulling,  as  a  rule  ? 

233.  Is  it  often  necessary  that  dyeings  on  worsted  yarns  should  be  par- 
ticularly fast  to  fulling?     Why  should  dyeings  on  woolen  yarns  be  fast  to 
fulling? 

234.  In  dyeing  piece-goods  of  woolen  material  is  it  necessary  to  select  dye- 
stuffs  which  are  fast  to  fulling?    What  is  meant  by  a  level-dyeing  dyestuff,  and 
why  is  this  class  preferred  for  piece-goods  ? 

235.  Under  what  conditions  may  it  be  necessary  to  dye  cotton  yarns  with 
colors  fast  to  fulling?    Are  other  solutions  besides  those  containing  soap  and 
alkali  ever  employed  for  fulling? 

236.  What  does  fastness  to  water  represent?    How  is  the  test  carried  out? 
To  what  materials  is  this  especially  applied  ? 

237.  If  a  color  is  fast  to-  scouring,  does  it  necessarily  signify  that  it  is  also 
fast  to  water?     Does  fastness  to  fulling  also  imply  fastness  to  scouring? 

238.  What  classes  of  fabrics  require  colors  having  fastness  to  perspiration? 
What  is  the  chemical  action  of  perspiration  ? 

239.  Describe  the  method  of  testing  a  color  for  its  fastness  to  perspiration. 
What  kind  of  acid  is  lactic  acid,  and  why  is  it  used  in  the  perspiration  test  ? 

240.  What  is  meant  by  "carbonizing"  as  applied  to  textiles?     Briefly  out- 
line the  method  of  carbonizing. 


TESTING   THE  FASTNESS  OF  COLORS.  1 1/ 

241.  What  classes  of  materials  are  carbonized?     Describe  the  method 
employed  in  testing  the  fastness  of  a  color  carbonizing. 

242 .  Would  colors  on  cotton  materials  ever  require  to  be  fast  to  carbonizing  ? 
What  other  processes  besides  treatment  with  solutions  of  sulphuric  acid  are 
employed  for  carbonizing? 

243.  What  is  meant  by  "cross-dyeing"?    How  is  the  test  representing 
fastness  to  cross-dyeing  carried  out  ? 

244.  The  dyeings  on  what  fibres  are  tested  for  fastness  to  cross-dyeing? 
How  does  the  test  for  cross-dyeing  differ  from  that  of  the  carbonizing  test  ? 

245.  What  is  meant  by  stoving?     How  is  the  process  conducted?    What 
classes  of  materials  are  subjected  to  stoving? 

246.  Describe  the  method  of  testing  a  color  for  fastness  to  stoving.     What 
is  the  chemical  action  of  sulphurous  acid  on  coloring-matters  ? 

247.  What  is  meant  by  chloring ?    What  kinds  of  dyed  materials  are  some- 
times chlored  ?    What  is  the  object  of  chloring  ? 

248.  How  is  the  test  for  bleaching  or  chloring  conducted?    Why  is  it 
necessary  to  treat  with  acidulated  water  ? 

249.  What  is  meant  by  "crocking"  ?     How  is  this  test  conducted?     Should 
well-dyed  materials  crock? 

250.  What  classes  of  dyed  materials  are  liable  to  crock,  and  explain  why? 
What  faults  in  dyeing  may  lead  to  lack  of  fastness  of  the  color  to  crocking? 

251.  What  qualities  of  fastness  should  dyeings  on  loose  wool  possess? 
Dyeings  on  shoddy  ? 

252.  What  should  be  the  requirements  for  fastness  of  worsted  weaving 
yarns  for  trouserings?     Of  worsted  knitting  yarns?     Of  hosiery  yarns  in 
general  ? 

2 53-  What  requirements  would  be  expected  in  colors  dyed  on  yarns  intended 
for  flannels,  blankets,  carriage  and  steamer  rugs,  and  plaid  dress-goods  ? 

254.  Yarns  employed  for  carpets  and  tapestries  require  colors  possessing 
what  qualities  of  fastness?     Yarns  for  plushes  and  velvets  require  what  fast- 
ness? 

255.  Fancy  weaving  yarns  of  cotton  for  all  cotton  dress-goods  and  shirtings 
require  what  qualities  of  fastness?    Dyed  cotton  yarns  to  be  employed  in 
union  goods  should  be  fast  to  what  tests  ? 

256.  Dyes  for  bookbinder's  cloth  should  have  what  qualities  of  fastness? 
Dyed  cotton  yarns  woven  in  towelling  should  be  fast  to  what  tests? 


SECTION  X. 
APPLICATION  OF  BASIC  DYES  TO  WOOL  AND  SILK. 

Experiment  67.  General  Method  of  Applying  Basic  Dyes  to 
Wool.  —  Basic  colors  are  usually  dyed  on  wool  in  neutral  or 
slightly  acid  baths.  Dye  a  skein  of  woolen  yarn  in  a  bath  con- 
taining 300  cc.  of  water,  2  per  cent,  of  acetic  acid,  10  per  cent, 
of  glaubersalt,  and  i  per  cent,  of  Methylene  Blue;  enter  at  100°  F., 
gradually  raise  to  180°  F.,  and  dye  at  that  temperature  for  one- 
half  hour  (202).  Dye  another  skein  of  woolen  yarn  in  a  similar 
bath  containing  10  per  cent,  of  glaubersalt  and  i  per  cent,  of 
Methylene  Blue  in  the  same  manner,  and  note  that  the  dyestuff 
is  absorbed  more  rapidly  (203).  The  function  of  the  acid  is  to 
retard  the  dyeing,  and  so  assist  in  the  even  distribution  and 
thorough  penetration  of  the  color.  If  the  bath  in  the  first  case 
does  not  exhaust  completely,  lift  the  skein  and  add  4  per  cent,  of 
borax,  and  continue  dyeing  for  15  minutes.  The  borax  is  a  mild 
alkali,  and  is  added  for  the  purpose  of  neutralizing  the  acid  in  the 
bath  and  so  permitting  the  complete  exhaustion  of  the  dyestuff. 
Acetic  acid  is  better  to  use  in  dyeing  basic  colors  than  sulphuric 
acid,  as  the  former  is  volatile,  and  as  the  temperature  of  the 
dye-bath  rises  the  acidity  becomes  lessened  and  consequently 
the  exhaustion  is  better. 

Experiment  68.  Showing  the  Effect  of  Hard  Water  on  Basic 
Dyes.  —  Dye  a  skein  of  woolen  yarn  in  a  bath  containing  300  cc. 
of  water  and  i  per  cent,  of  Magenta;  enter  at  100°  F.,  gradually 
bring  to  180°  F.,  and  dye  at  that  temperature  for  one-half  hour 
(204).  At  the  same  time  dye  a  second  skein  in  a  similar  bath  to 
which,  however,  there  is  added  5  cc.  of  lime  water  (205).  Carry 
out  the  dyeing  in  the  same  manner,  and  note  any  difference  in  the 
appearance  of  the  two  skeins  after  dyeing.  Lime  salts  in  water 

118 


APPLICATION  OF  BASIC  DYES  TO   WOOL  AND  SILK.    1 19 

cause  a  precipitation  of  basic  dyes  in  the  bath,  and  hence  inter- 
fere with  their  dyeing  properties. 

Experiment  69.  Showing  the  Greater  Coloring  Power  of  Basic 
Dyes  over  Acid  Dyes.  —  Dye  a  skein  of  woolen  yarn  in  a  bath  con- 
taining 300  cc.  of  water,  10  per  cent,  of  glaubersalt,  4  per  cent,  of 
sulphuric  acid,  and  2  per  cent,  of  Acid  Magenta;  enter  at  140°  F., 
gradually  raise  to  the  boil  and  dye  at  that  temperature  for  one- 
half  hour  (206).  Dye  a  second  skein  in  a  bath  containing  300  cc. 
of  water,  10  per  cent,  of  glaubersalt,  and  2  per  cent,  of  Magenta; 
dye  for  the  same  length  of  time  and  under  similar  conditions  as 
above  (207).  After  dyeing,  wash  and  dry  the  two  skeins.  Note 
the  depth  of  color  on  each,  and  it  will  be  found  that  the  skein  dyed 
with  the  acid  color  is  considerably  lighter  than  the  one  dyed  with 
the  basic  color. 

Experiment  70.  Use  of  a  Neutral  Bath.  —  Most  basic  dyes 
will  dye  fairly  well  on  wool  from  neutral  baths,  though  the  water 
used  should  be  soft,  or,  if  hard,  should  be  corrected  by  the 
addition  of  acetic  acid.  For  each  degree  of  hardness  of  the 
water  about  f  oz.  of  acetic  acid  should  be  added  per  100 
gallons  of  water.  Or  perhaps  a  more  convenient  method  is 
to  add  acetic  acid  to  the  water  of  the  dye-bath  until  it  shows  a 
faint  acid  reaction  with  litmus  paper  (turning  blue  litmus  paper 
red).  The  color  is  more  apt  to  be  uneven  from  neutral  baths 
than  from  those  containing  acid.  Dye  a  skein  of  woolen  yarn  in 
a  bath  containing  300  cc.  of  water,  10  per  cent,  of  glaubersalt, 
and  i  per  cent,  of  Rhodamine;  enter  at  100°  F.,  gradually  bring 
to  1 80°  F.,  and  continue  at  that  temperature  for  one-half  hour. 
Wash  and  dry  (208). 

Experiment  71.  Dyeing  Silk  with  Basic  Colors.  —  Dye  a  test- 
skein  of  silk  in  a  bath  containing  150  cc.  of  water,  25  cc.  of 
boiled-off  liquor,  and  2  per  cent,  of  Magenta;  enter  the  skein 
at  120°  F.,  and  gradually  bring  to  180°  F.,  and  dye  at  that  tem- 
perature for  one-half  hour,  then  wash  well  and  dry  (209) .  Silk, 
like  wool,  has  a  direct  affinity  for  the  basic  colors. 

Experiment  72.  Dyeing  Silk  in  a  Neutral  Soap  Bath.  —  Pre- 
pare a  bath  containing  150  cc.  of  water,  5  per  cent,  of  soap  (which 


120  DYEING  AND    TEXTILE  CHEMISTRY. 

should  be  a  neutral,  olive  oil  soap).  Work  the  test-skein  of 
silk  in  this  bath  for  a  short  time  at  140°  F.,  then  add  2  per  cent, 
of  Methylene  Blue  solution  in  several  portions,  at  the  same  time 
raising  the  temperature  of  the  bath  to  180°  F.  Continue  at  this 
temperature  for  15  minutes,  then  add  sufficient  acetic  acid  to 
slightly  acidulate  the  bath,  and  continue  dyeing  for  15  minutes 
longer.  Then  wash  well  and  brighten  with  acetic  acid  in  the 
manner  given  in  Exp.  51  (210).  Dye  a  second  sample  of  silk 
in  the  same  manner  with  2  per  cent,  of  Rhodamine  (211). 

Experiment  73.  After-Treatment  of  Basic  Dyes  on  Silk  with 
Tannin.  —  Dye  a  test-skein  of  silk  with  2  per  cent,  of  Methyl 
Violet  as  described  in  Exp.  72;  wash  well  (212)  and  pass 
into  a  fresh  bath  containing  100  cc.  of  water  and  i  gram  of 
tannic  acid;  work  for  20  minutes  at  180°  F.,  then  sink  under  the 
liquor  and  leave  for  one-half  hour  without  further  heating. 
Squeeze  out  the  excess  of  liquor  and  work  in  a  fresh  bath  con- 
taining 100  cc.  of  water  and  0.5  gram  tartar  emetic  at  a  tempera- 
ture of  140°  F.  for  20  minutes.  Wash  well  and  brighten  with 
acetic  acid  as  usual  (213).  Dye  a  second  skein  of  silk  in  the  same 
manner  with  2  per  cent,  of  Malachite  Green  (214). 

NOTES. 

i.  The  Use  of  Basic  Dyes  on  Wool  and  Silk.  —  The  basic  dyes 
are  very  largely  employed  on  silk,  for  the  silk  fibre  has  a  strong 
affinity  for  these  coloring-matters,  and  the  methods  of  their  appli- 
cation are  simple.  Furthermore,  the  colors  obtained  with  the 
basic  dyes  are  especially  characterized  by  depth  and  brilliancy, 
factors  which  are  very  important  in  dyeing  silk.  On  account  of 
the  strong  affinity  of  basic  colors  for  silk,  it  is  not  always  wise  to 
add  all  of  the  required  dyestuff  at  once  to  the  bath,  but  in  several 
portions  as  the  dyeing  proceeds.  Especial  care  must  be  taken  in 
the  solution  of  the  basic  dyes,  as  if  boiling  water  is  employed  for 
this  purpose  there  is  liability  of  tarry  matters  being  formed  by  a 
partial  decomposition  of  the  dyestuff.  It  is  best  to  use  warm 
water  acidified  with  acetic  acid.  In  some  cases  the  dyes  are  more 
readily  dissolved  if  a  little  methylated  alcohol  is  added.  Acetin, 


APPLICATION  OF  BASIC  DYES   TO   WOOL  AND   SILK.    121 

which  is  a  preparation  from  acetic  acid  and  glycerin,  is  sometimes 
employed  for  assisting  the  solution  of  basic  dyes.  The  basic  dyes 
at  the  present  time  do  not  find  much  application  on  woolen  goods, 
as  better  results  are  generally  to  be  obtained  by  the  use  of  acid 
colors.  In  former  years,  the  basic  colors  were  much  more  used 
than  they  are  now  for  wool;  but  by  treatment  with  sulphuric  acid 
many  of  the  basic  dyes  can  be  converted  into  corresponding  acid 
derivatives  which  are  used  instead.  Thus,  Magenta  gives  Acid 
Magenta,  Malachite  Green  furnishes  Acid  Green,  Methyl  Violet 
is  converted  into  Acid  Violet,  etc.  The  affinity  of  basic  dyes  for 
wool  is  very  great,  hence  they  are  liable  to  dye  up  uneven  unless 
proper  precautions  are  taken,  such  as  adding  the  dye  solution  to 
the  bath  in  several  portions,  starting  the  dyeing  at  a  low  tempera- 
ture, adding  some  acetic  acid  or  alum  to  the  bath,  etc.  For  the 
same  reason  the  basic  dyes  give  good  exhaustion  in  the  dye-bath, 
and  it  is  seldom  necessary  to  employ  standing  baths.  The  temper- 
ature when  dyeing  basic  colors  is  seldom  brought  to  over  180°  F., 
as  higher  temperatures  may  cause  decomposition  of  the  dyestuff 
(especially  noticeable  in  the  case  of  Auramine),  leading  to  the 
formation  of  sticky,  insoluble,  tarry  products.  As  the  basic  colors 
are  quite  sensitive  to  hard  water,  it  is  always  necessary  to  correct 
such  water  by  the  proper  addition  of  acetic  acid.  Rhodamine  is 
quite  extensively  used  on  wool  for  the  production  of  bright  pink 
colors;  the  dyed  material  may  be  bleached  with  sulphurous  acid 
gas,  which  considerably  brightens  up  the  color  and  also  gives  it 
greater  fastness  to  light.  Rhodamine  pinks  are  sufficiently  fast 
to  washing  for  most  purposes.  The  basic  colors  are  especially 
serviceable  in  the  dyeing  of  weighted  silks  where  the  weighting  has 
been  done  with  tin  salts.  The  after-treatment  with  tannic  acid 
and  tartar  emetic  is  for  the  purpose  of  giving  greater  fastness  to 
washing.  Colors  obtained  with  basic  dyes  on  wool  are  as  a  rule 
not  very  fast  to  light  or  washing,  and  also  exhibit  a  tendency  to 
crock.  Dye  spots,  consisting  of  uneven  streaks  or  spots,  often 
occur  when  dyeing  with  basic  colors,  caused  by  precipitation  of 
the  color-base  in  the  dye-bath  either  by  the  use  of  hard  water  or 
by  imperfect  solution. 


122  DYEING  AND   TEXTILE  CHEMISTRY. 

SAMPLES. 

202.  Showing  application  of  basic  dye  on  wool. 

203.  Dyed  with  glaubersalt  in  bath. 

204.  Magenta  dyed  with  soft  water. 

205.  Magenta  dyed  with  hard  water. 

206.  Dyeing  with  2  per  cent.  Acid  Magenta. 

207.  Dyeing  with  2  per  cent.  Magenta  (basic). 

208.  Rhodamine  dyed  in  neutral  bath. 

209.  Showing  application  of  basic  dye  to  silk. 

210.  Dyeing  silk  in  a  neutral  soap  bath. 

211.  Rhodamine  on  silk. 

212.  Methyl  Violet  before  treatment  with  tannin. 

213.  Methyl  Violet  after  treatment  with  tannin. 

214.  Malachite  Green  on  silk. 

QUIZ  10. 

257.  In  what  character  of  dye-bath  are  basic  dyes  usually  applied  to  wool? 
How  does  the  application  of  basic  dyes  differ  from  that  of  acid  dyes  ? 

258.  At  what  temperatures  are  basic  colors  generally  dyed?    Explain  the 
reason  for  this. 

259.  When  acid  is  added  to  the  dye-bath  in  dyeing  basic  colors,  what  is  its 
function  ?     What  acid  is  best  to  employ,  and  why  ? 

260.  Why  is  borax  at  times  added  in  dyeing  basic  colors?     Borax  has 
what  chemical  character?    What  is  borax? 

261.  What  is  meant  by  "hard"  water?     What  action  does  hard  water  have 
on  basic  colors  ? 

262.  Of  acid  and  basic  dyes,  which  have  the  greater  coloring  power? 
Compare  Acid  Magenta  and  Magenta  for  intensity  of  coloring  power. 

263.  How  may  hard  water  be  corrected  for  use  in  dyeing  basic  colors? 
What  is  meant  by  a  "degree"  of  hardness? 

264.  How  much  acetic  acid  per  100  gallons  of  water  is  necessary  to  add  to 
correct  each  degree  of  hardness  ?    If  the  degrees  of  hardness  of  the  water  are 
not  known,  how  could  you  tell  how  much  acetic  acid  to  add  to  the  water  ? 

265.  What  color  does  Rhodamine  give  on  wool,  and  how  is  it  dyed?    What 
peculiarity  is  to  be  noticed  with  respect  to  this  color  ? 

266.  What  is  the  general  method  for  dyeing  silk  with  basic  colors?    What 
is  boiled-off  liquor?    What  is  its  function  in  the  dye-bath?    What  substitutes 
may  be  employed  in  its  place  ? 

267.  Give  the  method  for  dyeing  silk  in  a  neutral  soap  bath.     What  kind 
of  soap  should  be  used?    Why  is  acetic  acid  added  at  the  end  of  the  dyeing 
operation  ? 


APPLICATION  OF  BASIC  DYES   TO   WOOL  AND   SILK.    12$ 

268.  What  is  meant  by  "brightening"  the  silk  after  dyeing,  and  how  is  this 
done? 

269.  How  may  basic  dyes  on  silk  be  after-treated  ?    Give  the  details  of  the 
process.     What  is  the  purpose  of  the  after-treatment  ? 

270.  Are  basic  dyes  at  the  present  time  largely  employed  on  wool  and  silk? 
What  are  the  special  characteristics  of  the  colors  obtained  by  the  use  of  basic 
dyes? 

271.  What  precautions  should  be  taken  to  obtain  level  shades  on  silk  with 
the  basic  dyes?     Why  are  they  liable  to  dye  up  unevenly? 

272.  What  precautions  should  be  taken  in  dissolving  basic  dyes?     Should 
boiling  water  be  used,  and  why  ? 

273.  Why  is  acetic  acid  added  to  the  water  in  dissolving  basic  dyes?     If 
the  dyes  are  but  slightly  soluble  in  water  what  solvent  should  be  used  ? 

274.  What  is  meant  by  "methylated  spirits"?    What  is  "acetin,"  and  of 
what  use  is  it  in  connection  with  basic  dyes  ? 

275.  Why  are  basic  dyes  not  much  employed  in  wool  dyeing  at  present? 
How  may  basic  dyes  be  converted  into  acid  dyes?    Mention  some  examples. 

276.  Why  are  basic  colors  liable  to  come  up  uneven  on  wool,  and  how  may 
this  be  prevented  ?    Do  basic  dyes  give  good  exhaustion  ? 

277.  Why  are  most  basic  dyes  not  dyed  at  the  boil?    Why  is  alum  some- 
times added  to  the  dye -bath  ? 

278.  How  may  a  clear  bright  pink  color  be  obtained  on  wool  ?    Why  is  the 
dyed  material  afterwards  stoved-or  sulphured,  and  what  effect  has  this  on  the 
fastness  of  the  color? 

279.  In  what  class  of  silk  dyeing  are  the  basic  colors  especially  serviceable, 
and  why  ?     How  may  greater  fastness  to  washing  be  obtained  ? 

280.  What  disadvantages  do  basic  dyes,. as  a  class,  have  in  wool  dyeing? 
What  is  meant  by  dye  spots;  what  causes  them,  and  how  may  they  be  prevented ? 


SECTION  XL 
BASIC  DYES  ON  COTTON. 

Experiment  74.  General  Method  of  Dyeing.  —  As  cotton  does 
not  possess  acidic  properties,  it  does  not  combine  directly  with 
basic  dyes,  but  requires  an  acid  substance  (mordant)  to  be  added 
to  the  fibre  in  order  for  the  dyeing  to  take  place.  Cotton  readily 
absorbs  tannic  acid  from  solution,  and  as  this  acid  forms  good 
color-lakes  with  the  basic  dyes,  it  is  a  very  suitable  mordant  for 
cotton  in  this  connection.  To  illustrate  this  reaction,  proceed 
as  follows:  Steep  a  skein  of  cotton  yarn  in  a  bath  containing 
300  cc.  of  water  and  2  per  cent,  of  tannic  acid;  enter  at  120°  F., 
raise  to  190°  F.,  then  allow  the  skein  to  remain  immersed  in  the 
bath  without  further  heating,  as  it  is  found  that  the  maximum 
amount  of  tannic  acid  is  absorbed  from  a  cooling  bath.  Now 
squeeze  the  skein  (215),  and  together  with  an  unmordanted  skein 
of  cotton  yarn  pass  into  a  dye-bath  containing  300  cc.  of  water 
and  i  per  cent,  of  Methylene  Blue;  enter  at  100°  F.,  gradually 
raise  to  190°  F.,  and  dye  at  that  temperature  for  one-half  hour; 
wash  well  and  dry.  It  will  be  found  that  the  mordanted  skein 
(216)  has  become  dyed,  whereas  the  other  skein  (217)  has  only 
become  slightly  tinted.  As  tannic  acid  is  liable  to  suffer  decom- 
position at  the  boil,  giving  rise  to  brown  coloring-matters  and 
resinous  products,  it  is  not  recommended  to  boil  the  mordanting 
bath,  as  the  shade  eventually  obtained  will  probably  be  dulled. 
The  tannin,  by  this  method  of  treatment,  is  not  held  in  an  insoluble 
state  in  the  cotton,  so  that  when  the  goods  are  placed  in  the  dye- 
bath  some  of  the  tannic  acid  passes  again  into  solution  in  the 
dye  liquor,  causing  some  of  the  dyestuff  to  be  precipitated  and 
also  causing  a  loss  of  color  to  the  fibre.  Hence  it  is  customary 
to  fix  the  tannic  acid  in  an  insoluble  condition  on  the  fibre  before 
passing  into  the  dye-bath,  as  will  be  described  in  a  succeeding 

124 


BASIC  DYES  ON  COTTON.  12$ 

experiment.  Tannin  is  a  vegetable  astringent  principle  and 
occurs  in  many  plants  or  vegetable  extracts,  such  as  sumac  (con- 
taining about  20  percent,  of  tannic  acid),  cutch  (containing  about 
40  per  cent,  of  tannic  acid) ,  etc.  These  vegetable  extracts  may  be 
used  in  place  of  tannic  acid  itself,  provided  sufficient  amount  of 
them  be  taken  to  give  the  proper  amount  of  actual  tannic  acid. 
Many  of  these  vegetable  extracts,  however,  also  contain  more  or 
less  brown  coloring-matters  associated  with  the  tannin,  and  these 
are  absorbed  by  the  cotton,  causing  the  latter  to  become  consider- 
ably colored  in  the  mordanting. 

Experiment  75.  Fixing  Tannin  on  Cotton  with  Tartar  Emetic. — 
In  order  to  fix  the  tannin  mordant  absorbed  by  the  cotton  from 
the  mordanting  bath  so  that  it  will  not  dissolve  into  the  dye-bath, 
it  is  best  to  combine  it  with  some  metallic  base  and  so  form  an 
insoluble  tannate.  Most  of  the  tannates  of  the  metals  are  dark 
in  color,  hence  unsuitable  for  dyeing,  except  for  the  production 
of  a  limited  range  of  shades.  The  tannate  of  antimony,  however, 
possesses  but  very  little  color,  and  scarcely  affects  the  resulting 
color  of  the  dye.  Tartar  emetic  is  potassium  antimony  tartrate, 
and  it  is  the  antimony  oxide  which  is  present  in  the  salt  which 
serves  the  purpose  of  fixing  the  tannin;  that  is,  the  tannin  reacts 
with  the  tartar  emetic  to  form  antimony  tannate.  Proceed  as  fol- 
lows :  Mordant  a  skein  of  cotton  yarn  in  a  bath  containing  300  cc. 
of  water  and  2  per  cent,  of  tannin  as  before  described;  squeeze 
and  pass  into  a  fresh  bath  containing  300  cc.  of  water  and  i  per 
cent,  of  tartar  emetic;  work  cold  for  15  minutes.  Then  wash  well 
in  fresh  water  (218)  to  remove  any  excess  of  the  antimony  com- 
pound and  any  unfixed  tannin,  and  pass  to  a  dye-bath  containing 
300  cc.  of  water,  i  per  cent,  of  Methyl  Violet,  and  2  per  cent,  of 
acetic  acid;  enter  at  100°  F.,  gradually  raise  to  190°  F.,  and  dye 
at  that  temperature  for  one-half  hour  (219).  The  amount  of 
tannin  used  in  mordanting  should  be  about  twice  that  of  the 
dyestuff,  and  the  amount  of  tartar  emetic  should  be  about  one- 
half  that  of  the  tannin.  The  acetic  acid  is  employed  for  the 
purpose  of  retarding  the  dyeing,  so  as  to  promote  even  and  well 
penetrated  colors. 


126  DYEING  AND   TEXTILE  CHEMISTRY. 

Experiment  76.  Fixing  Tannin  with  Copperas.  —  Copperas  is 
iron  sulphate,  and  as  it  occurs  in  the  form  of  green  crystals,  it 
is  known  as  "green  vitriol.'*  Salts  of  iron  combine  with  tannic 
acid  to  give  black  tannate  of  iron,  hence  tannin  fixed  on  cotton 
with  copperas  or  other  iron  salts  gives  the  fibre  a  gray  to  black 
color,  which,  of  course,  affects  the  shade  eventually  dyed  on  the 
mordant.  Mordant  a  skein  of  cotton  yarn  in  the  manner  de- 
scribed above  with  2  per  cent,  of  tannin,  squeeze,  and  steep  for 
15  minutes  in  a  cold  bath  containing  300  cc.  of  water,  5  per  cent, 
of  copperas  and  5  per  cent,  of  whiting.  The  latter  is  calcium 
carbonate  or  chalk,  and  is  added  in  order  to  keep  the  bath  neutral, 
for  when  the  tannic  acid  combines  with  the  iron  of  the  copperas 
there  is  liberated  some  sulphuric  acid,  and  as  tannate  of  iron  is 
soluble  in  sulphuric  acid,  it  will  be  redissolved.  The  chalk  in  the 
bath  combines  with  the  sulphuric  acid  as  fast  as  formed,  and 
thus  keeps  the  bath  neutral,  so  that  the  iron  is  able  to  combine 
fully  with  the  tannic  acid.  Wash  the  mordanted  skein,  which 
will  now  have  a  gray  or  slate  color,  and  preserve  a  sample  for 
comparison  (220),  then  dye  the  rest  of  the  skein  in  a  bath  con- 
taining 300  cc.  of  water,  i  per  cent,  of  Methylene  Blue  and  2  per 
cent,  of  acetic  acid  in  the  usual  manner.  Wash  and  dry  (221). 
In  the  same  bath  with  this  skein  also  dye  a  skein  of  cotton  yarn 
which  has  been  mordanted  in  the  usual  manner  with  tannin  and 
fixed  with  tartar  emetic.  Notice  the  difference  in  the  colors 
obtained,  due  to  the  iron  mordant;  also  compare  the  mordant 
color  with  the  dyed  color,  and  note  the  influence  of  the  bottom 
color  of  the  mordant  on  the  resulting  color-lake. 

Experiment  77.  Use  of  Other  Agents  in  Dyeing  Basic  Dyes. — • 
Mordant  a  test-skein  of  cotton  yarn  in  a  bath  containing  300  cc. 
of  water  and  20  per  cent,  of  sumac,  extract.  Enter  at  190°  F., 
work  the  cotton  in  the  bath  for  15  minutes,  then  steep  under 
the  liquor  for  i  hour  without  further  heating.  Squeeze  the  skein 
and  pass  into  a  fresh  bath  containing  300  cc.  of  water  and 
2  per  cent,  of  antimony  salt  (a  double  salt  of  antimony  fluoride 
with  ammonium  sulphate);  work  cold  for  15  minutes,  then  wash 
well  (222)  and  dye  in  a  fresh  bath  containing  300  cc.  of  water, 


BASIC  DYES  ON  COTTON.  I2/ 

5  per  cent,  of  alum,  and  2  per  cent,  of  Thioflavine  T.     Conduct 
the  dyeing  operation  as  usual.     Wash  well  and  dry  (223). 

Experiment  78.  Dyeing  Basic  Colors  in  One  Bath.  —  Prepare 
a  cold  bath  containing  300  cc.  of  water,  6  per  cent,  of  acetic  acid, 
2  per  cent,  of  tannic  acid,  and  i  per  cent,  of  Malachite  Green. 
Dye  a  skein  of  cotton  yarn  in  this  bath  cold  for  15  minutes,  then 
raise  the  temperature  to  105°  F.  for  15  minutes,  and  finally  to 
140°  F.  for  15  minutes;  then  rinse  the  skein,  squeeze,  and  dry 
(224).  The  fastness  to  washing  of  the  colors  dyed  in  this  manner 
may  be  increased  by  first  rinsing  after  dyeing  in  water  contain- 
ing J  to  2  per  cent,  of  tartar  emetic.  This  method  is  only 
applicable  to  amounts  of  dyestuff  up  to  about  i  per  cent.  The 
color-lake  is  held  in  solution  by  the  presence  of  the  acetic  acid, 
and  only  separates  out  gradually  in  the  fibre  on  heating  the  bath. 

Experiment  79.  Use  of  the  Janus  Dyes.  —  These  dyestuffs 
are  basic  colors  which  also  possess  substantive  or  direct  dyeing 
properties,  though  to  form  a  fast  color-lake  it  is  necessary  to 
fix  the  dye  with  tannin.  Prepare  a  dye-bath  containing  300  cc. 
of  water,  2  per  cent,  of  acetic  acid,  5  per  cent,  of  zinc  sulphate,  and 
2  per  cent,  of  Janus  Red.  Add  only  a  portion  of  the  dyestuff 
solution  at  first;  enter  the  cotton  skein  at  about  200°  F.,  work  for 
10  minutes,  then  add  the  remainder  of  the  dyestuff;  work  for 
10  minutes  longer,  and  then  add  20  per  cent,  of  common-salt, 
and  work  for  one-half  hour  at  the  boil.  Rinse  the  dyed  cotton 
(225),  and  pass  into  a  fixing  bath  containing  300  cc.  of  water, 
4  per  cent,  of  tannic  acid;  work  cold  for  15  minutes;  then  lift  the 
skein  and  add  to  the  bath  2  per  cent,  of  tartar  emetic  and  i  per 
cent,  of  sulphuric  acid,  and  work  cold  for  1 5  minutes  longer,  then 
raise  the  temperature  to  140°  F.  for  15  minutes.  Finally  wash 
well  and  dry  (226). 

NOTES. 

Substances  Employed  for  Mordanting  Cotton.  —  Tannins.  By 
the  general  term  "  tannins"  is  meant  a  number  of  related  organic 
acids  which  occur  as  the  astringent  principles  in  vegetable  life. 
They  are  generally  analogous  in  their  chemical  properties  and  are 
characterized  by  their  property  of  tanning  animal  skins  (that  is, 


128  DYEING  AND    TEXTILE   CHEMISTRY. 

converting  the  animal  tissue  into  leather) ,  forming  insoluble  com- 
pounds with  albumen,  precipitating  basic  dyes  from  solution,  and 
yielding  bluish  or  greenish  black  colors  with  solutions  of  iron  salts. 
The  majority  of  the  natural  tannins  also  contain  yellowish  or 
brownish  coloring-matters;  pure  tannic  acid,  however,  has  no 
special  color.  Some  of  the  tannins,  such  as  decoctions  of  gall- 
nuts  and  extracts  of  sumac,  may  be  almost  entirely  decolorized 
by  proper  methods  of  treatment.  Where  delicate  and  bright 
colors  are  to  be  obtained  on  cotton  with  basic  dyes  it  will  be 
necessary  to  employ  either  pure  tannic  acid  or  a  decolorized 
sumac  extract. 

Though  cotton  is  in  general  very  inert  towards  solutions  of 
organic  acids,  it  appears  to  possess  considerable  affinity  for  tannic 
acid,  and  will  absorb  it  readily  from  its  solutions.  Tannins 
should  be  stored  in  a  dry  place,  as  continued  exposure  to  damp 
air  will  cause  the  tannic  acid  to  decompose,  giving  brownish- 
colored  resinous  substances.  The  following  are  the  most  impor- 
tant tannins  employed  in  the  mordanting  of  cotton:  (i)  Tannic 
acid,  or  gallo-tannic  acid,  is  prepared  especially  from  gall-nuts, 
which  are  very  rich  in  this  acid.  Tannic  acid  comes  on  the 
market  in  the  form  of  a  light  brown  powder  or  yellowish  to 
brownish  scales  which  usually  darken  somewhat  on  exposure  to 
light.  It  is  soluble  in  6  parts  of  cold  water,  and  in  even  a  less 
quantity  of  hot  water;  it  is  also  freely  soluble  in  alcohol,  dilute 
acetic  acid,  and  glycerin.  Solutions  of  tannic  acid,  and  also  of 
any  of  the  tannins,  will  gradually  undergo  fermentation  and 
become  destroyed.  In  order  to  prevent  this  decomposition  in 
standing  baths  used  for  mordanting,  it  is  advisable  to  boil  up  the 
baths  repeatedly  or  to  add  a  small  amount  of  carbolic  acid  to 
them.  When  used  as  a  standing  bath  about  70  per  cent,  of  the 
amount  of  tannin  originally  added  to  the  first  bath  should  be  used 
for  replenishing.  (2)  Sumac  is  next  in  importance  to  tannic 
acid  itself  for  purposes  of  dyeing  cotton.  The  sumac  from  the 
Rhus  coriaria  is  considered  the  best  and  it  contains  gallo-tannic 
acid.  Sicilian  sumac  is  the  best  and  least  colored  variety;  after 
this  comes  the  American  (Virginian)  sumac,  which  can  now  be 


BASIC  DYES  ON  COTTON.  1 29 

obtained  in  very  good  qualities.  Commercial  sumac  usually 
consists  of  the  whole  or  the  crushed  or  pulverized  leaves,  though 
the  stalks  and  small  stems  are  frequently  admixed.  Good  quali- 
ties have  an  olive-green  color  and  a  pleasant  smell;  they  contain 
from  15  to  20  per  cent.,  and  sometimes  as  high  as  25  per  cent,  of 
tannin.  Sumacs  which  are  dull  in  color  and  of  a  musty  smell 
have  deteriorated  by  exposure  to  moist  air  and  prolonged  storing. 
Sumac  contains  a  small  amount  of  dull  reddish  brown  coloring- 
matter,  which  prohibits  its  use  in  most  cases  for  light  and  brilliant 
shades,  so  that  it  is  chiefly  employed  for  dark  shades.  Sumac 
extract  is  a  thick  dark  brown  liquid  or  paste,  usually  of  about 
52°  Tw.  density.  It  also  occurs  in  the  solid  state.  Decolorized 
sumac  extracts  are  also  to  be  had,  and  may  be  used  in  place  of 
pure  tannic  acid  for  light  colors.  Liquid  sumac  extracts  are  very 
.liable  to  fermentation,  especially  if  kept  in  a  warm  moist  room. 
(3)  Galls,  or  gall-nuts,  are  ball-shaped  excrescences  which  grow  on 
various  plants,  especially  oak  trees,  and  result  from  the  sting  of 
an  insect  in  depositing  its  eggs.  Of  the  oak-galls,  the  green  or 
black  Aleppo  galls  and  the  Turkish  or  Levant  galls  are  the  best 
and  contain  about  55  to  60  per  cent,  of  gallo-tannic  acid.  Chinese 
and  Japanese  galls  contain  up  to  80  per  cent,  of  gallo-tannic  acid, 
and  these  are  principally  used  for  the  production  of  pure  tannic 
acid.  (4)  Myrobolans  consist  of  the  fruit  of  several  Chinese  and 
Indian  plants,  and  they  occur  in  trade  in  the  dry  state;  they 
contain  25  to  45  per  cent,  of  tannin  and  a  yellowish  brown  color- 
ing matter.  They  are  not  much  used  in  this  country,  though 
sometimes  employed  for  dyeing  cotton  black.  (5)  Dim-dim  is  the 
fruit  of  certain  plants  in  Central  and  South  America;  they  contain 
20  to  35  per  cent,  of  tannin,  and  are  used  in  the  same  way  as  my- 
robolans.  There  are  many  other  tannin  substances  which  are 
more  or  less  locally  employed  where  they  are  to  be  obtained  in 
abundance,  but  the  above-mentioned  varieties  are  the  principal 
ones  to  be  met  with  in  trade.  In  the  mordanting  of  cotton  for 
dyeing,  i  pound  of  pure  tannic  acid  is  equivalent  to  about  ij  to 
2  pounds  of  gall-nuts,  or  4  pounds  of  sumac  extract  of  25  per  cent, 
strength,  or  to  5  to  6  pounds  of  sumac  leaves. 


I3O  DYEING  AND    TEXTILE   CHEMISTRY. 

Tartar  Emetic  and  Antimony  Salts.  —  Tartar  emetic  is  the 
double  tartrate  of  antimony  and  potassium;  it  is  a  crystalline 
salt  and  is  not  very  soluble  in  cold  water,  but  it  is  rather  easily 
soluble  in  hot  water.  One  part  of  the  salt  requires  about  13  parts 
of  water  for  solution  at  70°  F.  and  only  about  3  parts  of  water  at 
1 80°  F.  The  active  principle  in  tartar  emetic  which  enters  into 
the  fixation  of  the  tannin  in  the  mordanting  of  cotton  is  the 
antimony  trioxide,  Sb2O3,  of  which  the  pure  salt  contains  43.4  per 
cent.  The  commercial  product  consists  of  fine  crystals  of  irregu- 
lar lumps  containing  about  43  per  cent,  of  antimony  trioxide.  It 
is  frequently  adulterated  with  cheaper  substances.  Though 
tartar  emetic  and  the  rest  of  the  salts  of  antimony  are  poisonous, 
no  ill  effects  need  be  feared  from  its  use  in  dyeing,  if  the  goods 
are  well  washed  after  mordanting.  As  tartar  emetic  is  rather  an 
expensive  chemical,  it  is  often  replaced  by  cheaper  salts  of  anti- 
mony, which  have  the  same  effect  in  the  fixation  of  the  tannic 
acid.  The  chief  substitutes  are  as  follows:  (i)  Antimony  salt, 
which  is  the  double  salt  of  antimony  fluoride  and  ammonium 
sulphate;  it  occurs  as  white  crystals,  of  which  140  parts  are  soluble 
in  100  parts  of  water.  The  solution  is  strongly  acid  and  corrodes 
glass  and  metals,  owing  to  the  hydrofluoric  acid  liberated.  Anti- 
mony salt  contains  47  per  cent,  of  antimony  trioxide;  hence  9  parts 
are  equivalent  to  10  parts  of  tartar  emetic.  (2)  Patent  salt,  or 
Double  antimony  fluoride,  is  antimony-sodium  fluoride.  It  is  also 
crystalline  and  readily  soluble,  and  likewise  corrodes  glass  and 
metals.  It  contains  66  per  cent,  of  antimony  trioxide;  hence 
65.8  parts  of  this  salt  are  equivalent  to  100  parts  of  tartar  emetic. 
Of  these  two  double  fluorides  of  antimony,  5  to  20  parts  are 
dissolved  in  1000  parts  of  water,  and  their  strong  acidity  is  neu- 
tralized by  the  addition  of  6  to  8  per  cent,  in  weight  of  soda  ash, 
or  just  enough  to  render  the  bath  slightly  turbid.  (3)  Antimony 
oxalate  is  the  double  oxalate  of  potassium  and  antimony,  and 
was  introduced  as  the  first  cheap  substitute  of  tartar  emetic;  it 
has  given  much  satisfaction,  but  has  been  nearly  superseded  by 
the  double  fluorides.  It  occurs  as  crystals  which  are  readily 
soluble  in  water,  but  which  dissociate  rapidly  into  an  insoluble 


BASIC  DYES  ON  COTTON. 

basic  oxalate  of  antimony  and  a  soluble  binoxalate.  It  contains 
only  25.1  per  cent,  of  antimony  trioxide,  as  against  43.4  per  cent, 
in  tartar  emetic;  though  it  is  claimed  to  replace  equal  weights  of 
the  latter,  as  it  combines  more  rapidly  with  tannic  acid.  (4)  Anti- 
monine  is  the  double  lactate  of  antimony  and  calcium.  It 
occurs  as  crystals  containing  15  per  cent,  of  antimony  trioxide; 
it  is  hygroscopic  and  very  readily  soluble.  It  should  be  employed 
in  a  weakly  acid  solution,  that  is,  with  the  addition  of  about 
2  gallons  of  acetic  acid  per  1000  gallons  of  liquor.  This  product 
is  quite  extensively  employed. 

The  fixing  bath  of  tartar  emetic,  like  that  of  the  tannin,  may  be 
employed  continuously,  being  freshened  up  accordingly.  As  the 
bath  becomes  acid  on  using,  due  to  the  removal  of  the  antimony 
trioxide,  a  little  soda  ash  should  be  added  from  time  to  time  to 
neutralize  the  acid  as  it  accumulates;  this  is  best  done  by  adding 
a  dilute  solution  of  soda  ash  until  a  slight  turbidity  is  apparent. 
If  the  liberated  tartaric  acid  is  allowed  to  accumulate  without 
being  neutralized,  it  will  act  so  as  to  redissolve  the  precipitated 
antimony  tannate,  and  thus  lessen  the  value  of  the  fixing  bath. 

SAMPLES. 

215.  Cotton  mordanted  with  tannic  acid. 

216.  Mordanted  cotton  dyed  with  Methylene  Blue. 

217.  Unmordanted  cotton  dyed  with  Methylene  Blue. 

218.  Cotton  mordanted  with  tannin  and  antimony. 

219.  Methyl  Violet  on  tannin-antimony  mordant. 

220.  Cotton  mordanted  with  tannin  and  copperas. 

221.  Methylene  Blue  on  tannin-iron  mordant. 

222.  Cotton  mordanted  with  tannin  and  antimony  salt. 

223.  Thioflavine  T  on  tannin-antimony  mordant. 

224.  Malachite  Green  dyed  in  one  bath. 

225.  Janus  Red  before  mordanting. 

226.  Janus  Red  after  mordanting  with  tannin-antimony. 

QUIZ  II. 

281.  In  order  that  cotton  may  combine  with  basic  dyes  how  must  it  be 
treated?     The  mordants  must  possess  what  chemical  character? 

282.  Why  is  tannic  acid  a  suitable  mordant  for  cotton  in  connection  with 
basic  dyes  ?    What  other  mordants  could  be  used  on  cotton  for  basic  dyes  ? 


132  DYEING   AND    TEXTILE   CHEMISTRY. 

283.  Describe  the  method  of  mordanting  cotton  with  tannic  acid.     Why 
is  the  cotton  allowed  to  cool  down  in  the  bath  ? 

284.  Does  the  cotton  exhaust  the  tannic  acid  from  solution?    How  much 
does  it  take  up? 

285.  Give  the  conditions  of  dyeing  the  basic  colors  on  cotton  mordanted 
with  tannic  acid.     At  what  temperatures  does  the  dyeing  take  place  ? 

286.  Why  is  it  recommended  not  to  boil  the  tannin  bath  in  mordanting 
cotton?     Does  the  fibre  hold  the  tannin  in  an  insoluble  condition  after  mor- 
danting ? 

287.  What  is  tannic  acid  and  from  what  is  it  obtained?    What  other  sub- 
stances besides  tannic  acid  do  most  vegetable  tannins  contain  ? 

288.  What  is  the  object  of  fixing  the  tannin  after  mordanting  and  before 
dyeing?    The  salts  of  what  metals  are  most  suitable  for  fixing  agents  for 
tannin,  and  why  ? 

289.  What  is  tartar  emetic?    What  is  the  active  substance  in  this  salt 
which  acts  as  the  fixing  agent  for  the  tannin  ? 

290.  What  compound  is  formed  in  the  fibre  when  tannic  acid  is  fixed  with 
tartar  emetic? 

291.  Describe  the  method  of  fixing  tannin  on  cotton  with  tartar  emetic. 
At  what  temperature  is  the  bath  used?    Why  does  a  separate  bath  from  the 
mordanting  have  to  be  used? 

292.  Explain  the  chemical  reaction  which  takes  place  between  the  tartar 
emetic  and  the  tannic  acid.     What  color  is  the  cotton  after  fixing  with  anti- 
mony? 

293.  Why  is  acetic  acid  added  to  the  dye-bath  in  dyeing  cotton  with  basic 
colors  ?    What  other  substances  may  be  employed  for  the  same  purpose  ? 

294.  Why  should  the  cotton  be  thoroughly  washed  after  the  tannin  mor- 
dant has  been  fixed  with  tartar  emetic?     Should  it  be  washed  after  mordanting 
with  tannin  and  before  fixing? 

295.  How  much  tannin  and  tartar  emetic  should  be  used  for  mordanting 
cotton  for  each  percentage  of  dyestuff  used  ? 

296.  Suppose  50  pounds  of  cotton  yarn  are  to  be  dyed  with  2^  per  cent,  of 
Methyl  Violet:  give  the  size  of  vat  required,  if  it  is  to  be  3  feet  deep  by  2  feet 
wide.     How  much  tannic  acid  and  how  much  tartar  emetic  would  be  required  ? 
If  sumac  were  used  in  place  of  tannic  acid,  how  much  would  be  required? 
How  many  quarts  of  acetic  acid  (sp.  gr.  1.031)  of  30  per  cent,  strength  would 
be  used?     How  many  quarts  of  Methyl  Violet  solution  containing  4  ounces 
per  gallon  ? 

297.  What  is  copperas?     By  what  other  name  is  it  commonly  known  in 
trade? 

298.  What  reaction  takes  place  between  tannic  acid  and  salts  of  iron? 
What  color  is  the  resulting  compound  ? 


BASIC  DYES  ON  COTTON.  133 

299.  Give  the  method  of  mordanting  cotton  with  tannin  and  copperas. 
What  class  of  shades  may  be  dyed  on  this  mordant  ? 

300.  What  is  whiting,  and  why  is  it  employed  in  the  fixing  bath  with  cop- 
peras?    Explain  the  chemical  reactions  which  take  place. 

301.  What  color  does  Methylene  Blue  give  on  the  tannin-iron  mordant? 
How  does  the  color  compare  with  that  obtained  with  the  same  dyestuff  on  a 
tannin-antimony  mordant  ? 

302.  How  much  sumac  extract  is  necessary  for  the  mordanting  of  cotton? 
How  does  the  color  of  the  sumac  mordant  compare  with  that  of  the  pure 
tannic  acid  mordant  ? 

303.  What  color  does  Thioflavine  T  give  on  mordanted  cotton?    What  is 
the  purpose  of  the  addition  of  alum  to  the  bath  ? 

304.  Give  the  method  of  dyeing  basic  colors  in  one  bath.     What  is  the 
maximum  amount  of  dyestuff  which  may  be  used  in  this  method?     What  is 
the  function  of  the  acetic  acid  in  the  bath  ?     How  may  the  colors  be  made 
faster  to  washing? 

305.  What  properties  does  the  class  of  Janus  dyes  possess  ?     How  are  these 
colors  dyed  on  cotton  ?    Why  is  the  dyestuff  to  be  added  in  several  portions  ? 
How  is  the  after-mordanting  process  for  the  Janus  colors  carried  out  ? 

306.  What  is  meant  by  the  general  term  "tannins"?    What  are  their 
general  chemical  reactions? 

307.  What  kind  of  coloring-matters  do  most  natural  tannins  contain? 
Can  vegetable  tannin  extracts  be  decolorized,  and  how  ? 

308.  When  delicate  or  bright  shades  are  to  be  obtained  on  cotton  with 
basic  dyes,  what  character  of  tannin  must  be  used  in  the  mordanting  ? 

309.  What  precautions  should  be  taken  in  the  storage  of  tannins?    What 
is  the  action  of  damp  air  on  tannin  extracts? 

310.  Name  the  principal  tannin  materials  employed  in  the  mordanting  of 
cotton. 

311.  From  what  is  tannic  acid  itself  chiefly  prepared?     How  does  it  occur 
in  trade?     Give  some  idea  as  to  its  solubility  in  water.     In  what  other  re- 
agents is  it  soluble  ? 

312.  Are  solutions  of  tannic  acid  at  all  stable  ?     How  should  standing  baths 
of  tannic  acid  be  preserved?     How  much  tannic  acid  does  cotton  absorb  from 
the  first  bath,  and  consequently  what  addition  of  tannin  is  needed  for  successive 
standing  baths  ? 

313.  From  what  plant  is  sumac  obtained?    Which  variety  of  sumac  is 
considered  the  best  ?    How  does  American  sumac  compare  with  others  ? 

314.  Of  what  does  commercial  sumac  usually  consist?    What  should  be 
its  appearance  ?    What  percentage  of  tannic  acid  does  it  contain  ? 

315.  Does  sumac  contain  any  coloring-matter,  and  can  it  be  used  for  light 
and  brilliant  shades  ? 


134  DYEING   AND    TEXTILE   CHEMISTRY. 

316.  How  does  sumac  extract  occur  in  trade?    Are  sumac  extracts  liable 
to  deterioration  on  storage? 

317.  What  are  galls  or  gall-nuts,  and  how  do  they  originate?     How  much 
tannin  do  the  best  galls  contain  ? 

318.  Of  what  do  myrobolans  consist?     How  much  tannin  do  they  contain ? 
For  what  kind  of  dyeing  are  they  sometimes  used  ? 

319.  What  is  divi-divi,  and  how  much  tannin  does  it  contain?      Give  the 
ratio  in  tannin  between  pure  tannic  acid,  gall-nuts,  sumac  extract,  and  sumac 
leaves. 

320.  How  does  tartar  emetic  occur  in  trade  ?     Give  some  idea  as  to  its 
solubility  in  water.     How  much  antimony  trioxide  should  pure  tartar  emetic 
contain  ?    How  much  is  usually  present  in  the  commercial  variety  ? 

321.  Are  salts  of  antimony  poisonous?    Do  they  appear  to  give  any  bad 
results  if  properly  employed  in  dyeing?    Name  the  chief  substitutes  of  tartar 
emetic. 

322.  Of  what  does  antimony  salt  consist?    How  does  it  compare  with 
tartar  emetic  as  to  solubility  and  the  amount  of  antimony  trioxide  it  contains  ? 
Of  what  character  is  its  solution  ? 

323.  What  is  "patent  salt  "?    How  does  it  compare  with  tartar  emetic  as 
to  solubility  and  amount  of  antimony  trioxide  present?    How  should  the 
solutions  of  the  antimony  fluorides  be  prepared  ? 

324.  Of  what  does  antimony  oxalate  consist?     How  does  it  react  when 
dissolved  in  water?     How  does  it  compare  with  the  antimony  fluorides  and 
tartar  emetic? 

325.  What  is  antimonine?     How  does  it  compare  with  tartar  emetic  as  to 
solubility  and  percentage  of  antimony  trioxide  present?    How  should  its 
solution  be  prepared  ? 

326.  May  the  fixing  baths  of  antimony  salts  be  employed  as  a  standing 
kettle,  and  if  so,  how  should  the  baths  be  treated  in  order  to  prevent  their 
deterioration  ? 


SECTION   XII. 
REPRESENTATIVE  BASIC  DYES. 

Experiment  80.  Principal  Basic  Dyes  on  Cotton.  —  Use  test- 
skeins  of  cotton  yarn  mordanted  in  the  manner  described  in 
Exp.  75  with  4  per  cent,  of  tannin  and  2  per  cent,  of  tartar 
emetic.  Prepare  the  dye-bath  with  2  per  cent,  of  alum  and  the 
dyestuffs  given  below;  enter  at  100°  F.,  gradually  raise  the  tem- 
perature to  1 80°  F.,  and  dye  at  that  point  for  one-half  hour; 
wash  well  and  dry. 

2  per  cent.  Bismarck  Brown  (227). 

2  per  cent.  Safranine  (228). 

2  per  cent.  Brilliant  Green  (229). 

2  per  cent.  New  Methylene  Blue  BB  (230). 

2  per  cent.  Tannin  Orange  R  (231). 

2  per  cent.  Victoria  Blue  B  (232). 

i  per  cent.  Rhodamine  (233). 

1  per  cent.  Brilliant  Phosphine  (234). 

2  per  cent.  Acridine  Red  (235). 
J  per  cent.  Irisamine  (236). 

Test  five  of  these  colors  for  fastness  to  light,  washing,  and 
crocking  (see  Exps.  57,  58,  and  66). 

RECORD    OF    RESULTS    OP    TESTS. 


Tests. 

i 

2 

3 

4 

5 

Liffht 

Soap  liquor 

i 
i 

\Vhite  wool                 

a 
& 

White  cotton  

• 

Crocking 

135 


136 


DYEING   AND    TEXTILE   CHEMISTRY. 


Experiment  81.  Principal  Basic  Dyes  on  Silk.  —  Use  a  dye- 
bath  containing  5  per  cent,  of  soap  and  slightly  acidify  by  the 
addition  of  sufficient  acetic  acid.  Enter  the  silk  at  about  100°  F., 
and  gradually  raise  to  190°  F.,  and  dye  at  that  temperature  for 
one-half  hour.  Wash  well,  and  brighten  by  passing  the  dyed 
skeins  through  a  bath  of  dilute  acetic  acid,  squeezing  and  drying 
without  washing.  Use  the  following  dyestuffs: 

1  per  cent.  Diamond  Fuchsine  (237). 

2  per  cent.  Diamond  Fuchsine  (238). 

3  per  cent.  Safranine  (239). 

1  per  cent.  Methylene  Blue  (240). 

2  per  cent.  Methylene  Blue  (241). 

1  per  cent.  Auramine  (242). 

2  per  cent.  Malachite  Green  (243). 
2  per  cent.  Bismarck  Brown  (244). 
J  per  cent.  Rhodamine  (245). 

2  per  cent.  Tannin  Orange  R  (246). 

Test  five  of  these  colors  for  fastness  to  water  (see  Exp.  60). 

RECORD    OP    RESULTS    OF    TESTS. 


Tests. 

i 

2 

3 

4 

5 

3  u 
•8  ° 

White  silk 

^g 

White  cotton       

NOTES. 

i.  The  Use  of  Basic  Colors  on  Cotton.  —  Though  the  basic 
dyes  possess  a  strong  affinity  for  the  animal  fibres,  and  may  be 
dyed  on  these  in  a  neutral  bath  without  any  other  addition  than 
the  dyestuff  itself,  cotton  (and  the  vegetable  fibres  in  general) 
possesses  but  a  very  slight  attraction  for  this  class  of  dyestuffs. 
A  few  of  the  basic  dyes,  such  as  Magenta,  Chrysoidine,  Bismarck 
Brown,  and  Methylene  Blue,  will  be  absorbed  to  a  certain  extent 


REPRESENTATIVE   BASIC  DYES. 

by  the  cotton  fibre;  but  most  of  the  color  may  be  washed  out  with 
cold  water,  and  almost  entirely  removed  with  a  warm  soap 
solution.  An  exception  must  be  mentioned  of  certain  dyes 
among  the  class  of  water-soluble  indulines,  such  as  Indazine, 
Indamine  Blue,  Toluylene  Blue,  Nigramine,  New  Gray,  Methylene 
Gray  and  Indoin  Blue,  which  give  dyeings  of  considerable  fastness 
on  cotton  with  no  other  addition  to  the  dye-bath  than  sodium 
acetate.  In  order  to  dye  cotton  with  the  basic  dyes  it  is  customary 
to  previously  mordant  the  material  with  tannin  and  antimony. 
It  may  be  considered  that  a  tannate  of  antimony  is  precipitated 
within  the  fibre  which  exhibits  a  strong  affinity  for  the  basic 
dyes  and  gives  with  them  an  insoluble  color-lake.  The  affinity 
between  the  dyestuff  and  the  antimony  tannate  is  usually  so 
great  that  it  is  difficult  to  obtain  uniform  colors  in  the  dyeing, 
as,  for  instance,  with  Methylene  Blue,  Nigramine,  etc.  On  this 
account  it  is  advised  not  to  add  all  of  the  dyestuff  to  the  bath  at 
once,  but  to  dissolve  it  up  and  add  the  solution  in  several  portions. 
Furthermore,  it  is  best  to  start  the  dyeing  at  a  low  temperature 
and  not  to  raise  the  temperature  too  rapidly.  As  a  rule,  it  will 
not  be  necessary  to  bring  the  bath  to  the  boil,  as  the  dyeing  is 
usually  complete  at  about  180°  F. 

In  the  dyeing  of  basic  colors  on  cotton  the  tannin  mordant 
may  be  applied  in  one  of  two  ways:  (i)  steeping  the  cotton  in  the 
solution  of  tannin  for  a  comparatively  long  time,  then  squeezing 
and  fixing  with  tartar  emetic  or  other  suitable  salt;  (2)  padding 
with  the  solution  of  tannin,  which  consists  in  impregnating  the 
cotton  with  a  strong  solution  for  a  short  time,  then  squeezing  and 
drying  or  fixing  first  with  an  antimony  salt.  The  first  method  is 
that  usually  employed  for  yarn  dyeing,  while  the  padding  method 
is  largely  used  in  cloth  dyeing  and  also  for  the  production  of  mor- 
danted cloth  for  purposes  of  printing.  In  the  steeping  process 
it  has  been  the  custom  to  lay  the  yarn  down  in  the  tannin  liquor 
over-night,  starting  at  a  temperature  somewhat  under  the  boiling 
point  and  allowing  to  cool;  it  is  a  question  as  to  whether  the 
cotton  will  absorb  much  more  tannin  in  this  time  than  in  a  couple 
of  hours.  From  experiments  which  have  been  performed  on  this 


138  DYEING   AND    TEXTILE   CHEMISTRY. 

point  it  would  seem  that  by  entering  the  cotton  at  a  temperature 
just  under  the  boil  and  allowing  it  to  steep  in  the  cooling  liquor 
for  about  2  hours  it  will  absorb  about  as  much  tannin  as  it 
would  if  the  steeping  was  continued  for  10  to  12  hours.  It  is 
best  to  start  the  steeping  at  a  temperature  near  the  boiling  point, 
chiefly  for  the  purpose  of  driving  out  air  bubbles  from  the  fibre 
and  causing  better  penetration  of  the  tannin  solution.  The  higher 
temperature  does  not  appear  to  influence  the  actual  absorption 
of  the  tannin  itself  by  the  cotton,  as  more  is  absorbed  from  a 
cooling  bath  than  from  one  in  which  a  high  temperature  is  main- 
tained. The  strength  of  the  tannin  bath  should  be  based  on  the 
amount  of  coloring-matter  to  be  subsequently  used,  it  being 
customary  to  take  about  twice  as  much  tannin  (as  tannic  acid  and 
corresponding  amounts  of  tannin  extracts  in  accordance  with  the 
percentage  of  tannic  acid  present)  as  dyestuff ;  that  is,  if  a  color 
is  to  be  obtained  requiring  about  2  per  cent,  of  dyestuff,  about 
4  per  cent,  of  tannin  should  be  used  for  mordanting.  Where  light 
shades  are  being  dyed  it  is  not  customary  to  preserve  the  tannin 
bath,  but  for  dark  heavy  shades,  where  baths  containing  4  to  10 
per  cent,  of  tannin  are  being  used,  it  is  best  to  use  the  baths 
continuously,  freshening  the  standing  bath  each  time  with  3  to 
4  per  cent,  of  tannin.  The  amount  of  liquor  used  in  the  mor- 
danting bath  should  not  be  more  than  15  to  16  times  the  weight 
of  the  cotton;  that  is,  each  pound  of  cotton  should  have  about 
2  gallons  of  water  for  mordanting;  if  a  greater  amount  of  water 
is  used,  the  proportion  of  tannin  absorbed  by  the  fibre  will  be 
lessened  and  a  correspondingly  larger  amount  of  tannin  will 
have  to  be  used.  The  water  employed  in  the  mordanting  bath 
should  be  as  free  from  iron  as  possible  if  the  tannin  is  to  be  fixed 
with  antimony;  for  iron  present  in  even  a  slight  trace  will  alter 
the  color  of  the  dyeing  considerably,  especially  in  the  case  of  pale 
shades.  If  the  water  does  contain  any  iron,  a  small  amount  of 
hydrochloric  acid  should  be  added  which  will  hold  the  iron 
tannate  in  solution  and  prevent  it  from  contaminating  the  fibre. 
Hard  water,  that  is,  a  calcareous  water,  unless  of  very  consider- 
able hardness,  is  not  especially  detrimental  for  use  with  tannin; 


REPRESENTATIVE   BASIC  DYES,  139 

if  there  is  much  lime  present,  it  may  result  in  the  precipitation  of 
some  of  the  mordant  in  the  form  of  tannate  of  lime.  Such  water 

0 

may  be  best  corrected  by  the  addition  of  sufficient  acetic  acid 
to  give  a  slight  acid  reaction  to  the  bath  previous  to  the  addition 
of  the  tannin.  After  the  steeping  in  the  tannin  is  completed, 
the  cotton  should  be  well  squeezed  or  wrung  out  to  remove  the 
excess  of  liquor;  in  practice  this  may  be  best  accomplished 
by  hydro-extraction.  It  is  not  advisable  to  rinse  the  cotton  after 
removal  from  the  tannin  bath,  as  this  will  only  result  in  redis- 
solving  some  of  the  absorbed  tannin,  and  the  residual  liquor 
in  the  cotton  will  still  be  a  solution  of  tannin;  so  that  the  rinsing 
does  not  serve  the  purpose  of  removing  such  residual  liquor, 
but  only  results  in  the  lessening  of  the  mordant.  There  does  not 
appear  to  be  much  difficulty  attached  to  the  uneven  squeezing 
or  wringing  of  the  mordanted  cotton  leading  to  uneven  results 
in  the  subsequent  dyeing;  probably  if  the  tannin,  through  one 
cause  or  another,  is  distributed  very  unevenly  through  the  cotton, 
there  may  result  uneven  dyeing,  yet  under  ordinary  conditions 
particular  caution  does  not  have  to  be  taken  in  the  even  squeezing 
of  the  wet  cotton. 

After  the  mordanted  cotton  is  squeezed  the  next  operation  is  to 
pass  through  a  fixing  bath  containing  tartar  emetic  or  other  suit- 
able salt  of  antimony.  The  fixing  is  complete  in  from  15  to  30 
minutes  and  a  cold  bath  is  used;  the  amount  of  tartar  emetic 
necessary  is  about  one-half  that  of  the  tannin  used;  in  other 
words,  it  is  about  equivalent  to  the  amount  of  dyestuff  to  be  used. 
For  other  antimony  salts,  corresponding  amounts  must  be  used 
(see  previous  section).  The  reaction  in  the  fixing  bath  consists 
of  the  formation  of  antimony  tannate  in  the  fibre,  and  it  should  be 
so  adjusted  that  all  of  the  tannin  present  is  thus  combined;  this 
reaction  necessitates,  of  course,  the  liberation  in  the  bath  of  the 
acid  previously  combined  with  the  antimony  —  with  tartar  emetic 
there  would  be  liberated  tartaric  acid.  On  this  account,  when 
using  the  fixing  liquor  as  a  standing  bath,  it  will  be  necessary  to 
add  sufficient  soda  ash  from  time  to  time  to  neutralize  the  acidity, 
otherwise  the  tannate  of  antimony  will  be  dissolved  from  the 


I4O  DYEING  AND   TEXTILE  CHEMISTRY. 

fibre.  When  the  fixation  of  the  tannin  mordant  is  completed  the 
cotton  must  be  thoroughly  washed  for  the  purpose  of  removing 
all  uncombined  tartar  emetic  or  tannin;  if  excess  of  either  of  these 
is  present  in  the  fibre  when  it  is  passed  into  the  dye-bath  it 
will  result  in  the  loss  of  coloring-matter  and  probably  lead  to 
streaked  and  imperfect  dyeing.  After  the  mordanting  and  fixing 
operations  are  finished  too  long  a  time  should  not  elapse  before 
the  dyeing,  for  if  the  mordanted  cotton  is  exposed  for  any  length 
of  time  to  the  air  and  light  the  exposed  parts  will  turn  somewhat 
brownish  and  after  dyeing  will  appear  duller.  If  the  dyeing 
cannot  be  carried  out  the  same  day  as  the  mordanting  and  fixing, 
the  material  should  be  covered  with  a  moistened  cloth. 

In  some  cases  in  order  more  thoroughly  to  combine  any  excess 
of  tartar  emetic  in  the  fibre  after  fixing,  the  cotton  is  passed 
back  into  the  tannin  bath  (usually  a  rather  weak  one).  This 
"back-tanning"  may  also  be  done  after  dyeing;  it  also  appears  to 
give  colors  which  are  faster  to  washing.  As  antimony  compounds 
are  of  a  poisonous  nature  they  should  be  thoroughly  fixed  in  the 
fibre,  as  otherwise  blood  poisoning  might  result  from  fabrics  worn 
next  the  skin.  In  certain  cases  (as  with  Victoria  Blue  and  Methy- 
lene  Blue)  in  order  to  obtain  even  shades  it  is  necessary  to  wash 
the  cotton  after  fixing  for  15  to  30  minutes  in  a  warm  soap  bath 
(containing  about  2  ounces  soap  to  10  gallons  of  water),  and 
afterwards  wash  in  fresh  water.  This  treatment  usually  pro- 
duces clearer  and  more  even  shades. 

In  the  dyeing  it  is  best  to  start  the  bath  cold,  using  25  to  30 
times  as  much  water  as  cotton  (one  pound  of  cotton  would  there- 
fore require  about  4  gallons  of  water) ,  and  adding  first  about 
i  to  i  J  per  cent,  of  acetic  acid;  this  serves  the  purpose  of  correcting 
any  hardness  in  the  water  and  thus  prevents  any  precipitation 
of  coloring-matter,  and  also  makes  the  bath  slightly  acid  which 
avoids  too  rapid  an  exhaustion  of  dyestuff  in  the  dyeing.  After 
the  acid  has  been  placed  in  the  bath  a  portion  of  the  color  solution 
is  added,  and  then  the  cotton  is  entered  and  worked  for  about 
10  minutes;  the  material  is  then  lifted,  and  a  further  portion  of 
the  dyestuff  solution  added,  the  bath  being  heated  to  about  100°  F. 


REPRESENTATIVE  BASIC  DYES.  141 

Finally  the  rest  of  the  color  is  added  and  the  bath  is  raised  to 
about  140  to  1 60°  F.,  and  the  dyeing  completed.  In  place  of 
acetic  acid,  an  addition  of  about  3  per  cent,  of  aluminium  sulphate 
or  5  per  cent,  of  alum  may  be  made.  In  the  case  of  certain  basic 
colors  the  dyeing  is  finished  by  raising  the  temperature  of  the 
bath  to  the  boil,  as  with  Naphthindone. 

When  the  tannin  mordant  is  to  be  fixed  with  iron  instead  of 
antimony,  where  dark  colors  are  to  be  employed,  the  fixing  bath  is 
made  up  with  3  to  5  per  cent,  of  copperas,  or  consists  of  pyrolignite 
of  iron  at  3  to  4°  Tw.  The  bath  is  employed  cold,  and  it  is  well 
to  add  a  small  quantity  of  chalk  (calcium  carbonate)  to  prevent 
the  accumulation  of  acid  (from  the  acid  combined  with  the  iron 
salt  and  which  will  be  liberated  when  the  iron  combines  with  the 
tannin  to  form  tannate  of  iron) ;  about  2  to  4  per  cent,  of  chalk  will 
be  all  that  is  necessary.  Dyeings  on  an  iron-tannin  mordant  are 
not  so  fast  as  those  on  an  antimony-tannin  base,  so  the  process  of 
fixing  with  iron  is  sometimes  modified  by  first  fixing  with  antimony 
and  subsequently  with  iron,  or  even  by  saddening  with  an  iron 
liquor  after  the  dyeing  is  finished. 

In  some  cases  increased  fastness  to  washing  for  basic  dyeings 
may  be  obtained  by  giving  the  dyed  goods  a  passage  through  the 
tannin  bath  (the  old  tannin  liquor  may  be  used),  wringing  out, 
and  then  passing  through  the  tartar  emetic  bath  again  and 
washing  well. 

Certain  of  the  basic  colors,  such  as  Naphthindone  and  Irisamine, 
may  be  dyed  on  cotton  directly  without  a  mordant.  The  dye- 
bath  is  prepared  with  3  to  5  pounds  of  salt  per  10  gallons  of  liquor 
according  to  the  depth  of  shade;  the  dyeing  is  started  at  110°  F., 
and  the  bath  is  slowly  brought  to  the  boil;  after  dyeing  the  goods 
are  simply  wrung  out  as  evenly  as  possible  and  dried.  This 
method  is  not  often  practiced,  as  the  colors  obtained  are  not  very 
fast  to  washing  or  light. 

For  the  production  of  bright  pinks  on  cotton  certain  basic  dyes, 
like  Irisamine,  may  be  used  on  a  mordant  of  Turkey-red  oil.  The 
yarn  is  mordanted  in  lots  of  i  pound  each  in  a  liquor  containing 
i  part  Turkey-red  oil  and  2  parts  of  water,  and  after  each  lot  is 


142  DYEING   AND    TEXTILE   CHEMISTRY. 

mordanted  about  i  pint  of  such  a  mixture  is  added'  afresh.  After 
mordanting,  the  yarn  is  wrung  out  well,  straightened  and  dried,  after 
which  the  same  treatment  is  repeated.  The  dyeing  is  conducted 
in  a  cold  concentrated  bath  with  addition  of  some  acetic  acid,  the 
color  solution  being  added  in  several  portions.  In  order  to  produce 
level  shades  it  is  necessary  that  the  yarn  be  wrung  out  as  evenly 
as  possible  and  that  the  mordanting  be  repeated  several  times. 

2.  List  of  the  Principal  Basic  Dyes.  —  The  basic  dyes  do  not 
include  such  a  large  list  as  the  acid  dyes,  though  the  apparent 
number  is  considerably  increased  by  the  fact  that  the  same  dye- 
stuff  is  frequently  given  a  variety  of  different  names,  and  fur- 
thermore, a  number  of  mixtures  are  marketed  under  specific 
names.  Some  of  these  dyes  are  more  adapted  to  the  dyeing 
of  silk  than  of  cotton,  and  vice  versa;  this  can  only  be  deter- 
mined by  reference  to  the  specific  properties  of  the  individual 

dyestuffs. 

(a)  RED. 

Acridine  Red.  Magenta  Scarlet. 

Acridine  Scarlet.  Maroon. 

Brilliant  Rhoduline  Red.  Neutral  Red. 

Cardinal.  Neutral  Scarlet. 

Cerise.  New  Magenta. 

Diamond  Fuchsine.  Parafuchsine. 

Diamond  Magenta.  Patent  Rhodamine. 

Fuchsine.  Pyronine. 

Grenadine.  Rhodamine. 

Induline  Scarlet.  Rhodine. 

Irisamine.  Rhoduline  Red. 

Isorubine.  Rosazeine. 

Janus  Bordeaux.  Rubine. 

Janus  Red.  Safranine. 
Magenta. 

(V)  ORANGE. 

Acridine  Orange.  •  Homophosphine. 

Azo  Phosphine.  New  Acridine  Orange. 

Brilliant  Phosphine.  New  Phosphine. 

Canelle.  Paraphosphine. 

Chrysoidine.  Patent  Phosphine. 

Coriphosphine,  Phosphine. 

Flavinduline.  Tannin  Orange. 


REPRESENTATIVE   BASIC  DYES.  143 

(c)  YELLOW. 

Acridine  Yellow.  Leather  Yellow. 

Auracine.  Rheonine. 

Auramine.  Thioflavine  T. 

Benzoflavine.  Xanthine. 
Janus  Yellow. 

(d)  GREEN. 

Azine  Green.  Malachite  Green. 

Bengal  Green.  Methyl  Green. 

Brilliant  Green.  Methylene  Green. 

Capri  Green.  New  Fast  Green. 

China  Green.  New  Green. 

Diamond  Green.  New  Solid  Green. 

Diazine  Green.  New  Victoria  Green. 

Ethyl  Green.  Victoria  Green. 
Janus  Green. 

(e)  BLUE. 

Azindone  Blue.  Fast  Blue. 

Basle  Blue.  Fast  Blue  for  cotton. 

Bavarian  Blue.  Fast  Cotton  Blue. 

Bengal  Blue.  Fast  Marine  Blue. 

Bleu  de  Lyon.  Fast  New  Blue. 

Bombay  Blue.  Gentianine. 

Brilliant  Blue.  Helvetia  Blue. 

Brilliant  Cresyl  Blue.  Indamine  Blue. 

Brilliant  Diazine  Blue.  Indanil  Blue. 

Brilliant  Metamine  Blue.  Indazine. 

Brilliant  Victoria  Blue.  Indigen. 

Capri  Blue.  Indigo  Blue. 

China  Blue.  Indoine. 

Cotton  Blue.  Indoine  Blue. 

Cotton  Light  Blue.  Indol  Blue. 

Cresyl  Blue.  Indone  Blue. 

Crystal  Fast  Blue.  Indophenine  Blue. 

Dark  Blue.  Janus  Blue. 

Diazine  Blue.  Janus  Dark  Blue. 

Diphene  Blue.  Light  Blue. 

Diphenylamine  Blue.  Marine  Blue. 

Ethyl  Blue.  Metaphenylene  Blue. 

Ethylene  Blue.  Methyl  Blue. 

Excelsior  Cotton  Blue.  Methyl  Cotton  Blue. 


144  DYEING  AND    TEXTILE   CHEMISTRY. 

(e)  BLUE.  —  Continued. 

Methyl  Indone.  Opal  Cotton  Blue. 

Methyl  Light  Blue.  Paper  Blue. 

Methyl  Water  Blue.  Paraphenylene  Blue. 

Methylene  Blue.  Peacock  Blue. 

Methylene  Dark  Blue.  Phenine  Blue. 

Methylene  Indigo.  Phenylene  Blue. 

Muscarine.  Pure  Blue. 

Naphthindone.  Rhoduline  Blue. 

Naphthol  Blue.  Rhoduline  Sky  Blue. 

Neutral  Blue.  Setocyanine. 

Neutral  Peacock  Blue.  Setoglaucine. 

New  Blue.  Setopaline. 

New  Diamond  Indigo  Blue.  Solid  Blue. 

New  Fast  Blue.  Thionine  Blue. 

New  Indigo  Blue.  Toluidine  Blue. 

New  Metamine  Blue.  Toluylene  Blue. 

New  Methylene  Blue.  Turkey  Blue. 

New  Solid  Blue.  Turquoise  Blue. 

New  Victoria  Blue.  Victoria  Blue. 

Night  Blue.  Victoria  Night  Blue. 

Nile  Blue.  Water  Blue. 

(/)  VIOLET. 

Brilliant  Rhoduline  Purple.  Methylene  Violet. 

Brilliant  Violet.  Neutral  Violet. 

Cresyl  Fast  Violet  Paraphenylene  Violet. 

Crystal  Violet.  Primula. 

Dahlia.  Red  Violet. 

Ethyl  Purple.  Regina  Violet. 

Ethyl  Violet.  Rhoduline  Heliotrope. 

Fast  Neutral  Violet.  Rhoduline  Violet. 

Girofle.  Rosolane. 

Heliotrope.  Rubine  Violet. 

Irisamine.  Soda  Violet. 

Iris  Violet.  Tannin  Heliotrope. 

Methyl  Violet.  Violet. 
Methylene  Heliotrope. 

(g)  BROWN. 

Bismarck  Brown.  Manchester  Brown. 

Brown  extra  soluble.  Tannin  Brown. 

Cutch  Brown.  Vesuvine. 
Janus  Brown. 


REPRESENTATIVE  BASIC  DYES.  145 

(h)  BLACK. 

Coal  Black.  Methylene  Gray. 

Diazine  Black.  New  Fast  Gray. 

Fast  Black.  New  Gray. 

Fast  Gray.  New  Methylene  Gray. 

Janus  Black.  Nigrisine. 

Janus  Gray.  Paper  Black. 

Jute  Black.  Silk  Gray. 

Jute  Coal  Black.  Straw  Black. 

Leather  Black. 

SAMPLES. 

227.  Bismarck  Brown  on  tannin-antimony  mordant  on  cotton. 

228.  Safranine  on  same. 

229.  Brilliant  Green  tm  same. 

230.  New  Methylene  Blue  BB  on  same. 

231.  Tannin  Orange  R  on  same. 

232.  Victoria  Blue  B  on  same. 

233.  Rhodamine  on  same. 

234.  Brilliant  Phosphine  on  same. 

235.  Acridine  Red  on  same. 

236.  Irisamine  on  same. 

237.  Diamond  Fuchsine  (i  per  cent.)  on  silk. 

238.  Diamond  Fuchsine  (2  per  cent.)  on  same. 

239.  Safranine  on  same. 

240.  Methylene  Blue  (i  per  cent.)  on  same. 

241 .  Methylene  Blue  (2  per  cent.)  on  same. 

242.  Auramine  on  same. 

243.  Malachite  Green  on  same. 

244.  Bismarck  Brown  on  same. 

245.  Rhodamine  on  same. 

246.  Tannin  Orange  R  on  same. 

QUIZ  12. 

327.  Name  five  of  the  principal  basic  dyes  applied  to  cotton.     What  colors 
do  they  give  ? 

328.  What  degree  of  fastness  did  you  find  for  the  colors  selected  when 
tested  to  light,  washing,  and  crocking? 

329.  Name  five  of  the  principal  basic  dyes  employed  on  silk,  with  the 
character  of  the  colors  they  give  on  this  fibre.     How  do  these  compare  in 
brightness  with  corresponding  acid  dyes  ? 


146  DYEING  AND   TEXTILE  CHEMISTRY. 

330.  What  was  the  result  of  your  tests  for  fastness  to  water  of  the  basic  dyes 
on  silk  ?    How  do  they  compare  in  this  respect  to  the  corresponding  acid  dyes 
which  were  tested  ? 

331.  Does  cotton  possess  any  direct  attraction  for  the  general  class  of  basic 
dyes  ?    Are  there  any  exceptions  to  this  general  rule  ? 

332.  In  order  to  dye  cotton  with  the  basic  dyes  what  previous  treatment  is 
necessary?     Of  what  does  the  mordant  consist?    How  does  this  mordant 
react  with  basic  dyes  ? 

333.  Is  the  attraction  of  the  basic  dyes  for  antimony  tannate  strong  or 
weak,  and  how  is  this  shown  in  the  dyeing? 

334.  What  precautions  are  recommended  in  the  dyeing  of  basic  colors  on 
cotton  in  order  to  obtain  level  shades  ? 

335.  In  what  two  ways  may  the  tannin  mordant  be  applied  to  cotton,  and 
for  what  classes  of  material  is  each  most  adaptable  ? 

336.  What  is  meant  by  "padding"  and  how  is  this  done?    What  kind  of  a 
solution  is  used  for  padding  ? 

337-   Give  the  process  of  mordanting  cotton  with  tannin  by  the  steeping 
process.    What  length  of  time  is  required  for  this  process? 

338.  Why  should  the  mordanting  bath  be  started  near  the  boiling  point? 
Under  what  conditions  is  the  greatest  amount  of  tannin  taken  up  by  the 
cotton  ? 

339.  How  should  the  strength  of  the  tannin  bath  be  regulated  ?    How  much 
tannin  should  you  use  for  the  dyeing  of  50  pounds  of  cotton  where  the  color 
calls  for  i£  per  cent,  of  dyestuff? 

340.  Is  it  possible  to  employ  the  tannin  solution  as  a  standing  bath  ?    How 
much  tannin  should  be  used  for  freshening  ? 

341.  How  many  pounds  of  sumac  extract  containing  20  per  cent,  of  tannin 
should  be  used  for  mordanting  75  pounds  of  cotton  yarn  which  are  to  be  dyed 
with  3  per  cent,  of  coloring-matter  ? 

342.  How  much  water  should  be  used  in  the  mordanting  bath  in  proportion 
to  the  weight  of  the  cotton  to  be  mordanted  ? 

343.  How  many  gallons  of  tannin  liquor  would  be  required  for  the  mor- 
danting of  75  pounds  of  cotton  yarn  ?     If  gambier  containing  35  per  cent,  of 
tannin  is  to  be  used  for  mordanting,  how  much  should  be  taken  if  the  cotton  is 
to  be  dyed  with  2  per  cent,  of  dyestuff? 

344.  What  character  of  water  should  be  used  in  the  tannin  bath?     If  the 
tannin  is  to  be  fixed  with  antimony  why  should  the  water  be  free  from  iron  ? 

345.  If  water  containing  iron  has  to  be  used  for  mordanting  with  tannin, 
how  may  it  be  corrected?     Explain  the  action  of  the  substance  used  for  cor- 
recting. 

346.  Can  calcareous  water  be  used  in  the  tannin  bath?    What  action  takes 
place  between  the  lime  and  the  tannin  ?     If  the  water  is  highly  calcareous  how 
may  it  be  corrected  for  use  in  the  tannin  bath  ? 


REPRESENTATIVE  BASIC  DYES. 

347.  After  the  cotton  has  been  steeped  in  the  tannin  solution  should  it  be 
rinsed  ?    Why  ? 

348.  In  the  wringing  out  of  the  cotton  after  mordanting  with  tannin  do 
particular  pains  have  to  be  taken  in  order  to  squeeze  out  the  liquor  evenly  ? 

349.  How  is  the  tannin  fixed  on  the  cotton  after  mordanting  ?    Why  is  this 
necessary  ? 

350.  How  is  the  fixing  bath  of  tartar  emetic  prepared?    How  long  does 
the  fixing  require  and  what  temperature?     How  much  tartar  emetic  should 
be  used? 

351.  If  75  pounds  of  cotton  are  to  be  dyed  with  ij  per  cent,  of  a  basic 
dyestuff,  how  many  pounds  of  tartar  emetic  should  be  used  for  fixing  the 
tannin  ? 

352.  How  much  antimony  salt  would  be  required  in  the  above  example? 
How  much  antimony  oxalate  and  how  much  antimonine  ? 

353-  What  reaction  takes  place  in  the  fixing  bath  of  tartar  emetic?    With 
antimony  fluoride  ?    With  antimony  oxalate  ?    With  antimonine  ? 

354.  If  the  antimony  fixing  liquor  is  used  as  a  standing  bath  what  addition 
is  necessary  and  why  ? 

355.  After  fixing  the  tannin  with  antimony  why  is  it  necessary  to  thoroughly 
wash  the  cotton?     What  defects  would  be  liable  to  occur  if  this  were  not 
done? 

356.  Should  the  dyeing  of  basic  colors  on  cotton  take  place  immediately 
after  the  mordanting  and  fixing,  and  why  ? 

357.  If  the  dyeing  on  the  mordanted  cotton  cannot  be  done  on  the  same  day 
what  should  be  done  with  the  material  ? 

358.  What  is  meant  by  "back -tanning"  ?    How  is  this  done  and  what  is  its 
purpose  ? 

359.  If  any  free  antimony  fixing  compound  is  left  in  the  goods  after  dyeing 
material  used  for  clothing,  what  defect  is  liable  to  arise  ? 

360.  In  order  to  insure  clear  even  shades  with  Victoria  Blue  how  should  the 
cotton  be  treated  after  fixing  ? 

361.  In  dyeing  cotton  with  basic  colors  at  what  temperature  should  the 
bath  be  started,  how  much  water  should  be  used,  and  what  addition  should  be 
made  before  the  color  is  added  ?    What  is  the  purpose  of  this  addition  ? 

362 .  In  what  manner  should  the  basic  dyestuff  be  added  to  the  dye-bath,  and 
how  should  the  temperature  of  the  bath  be  regulated  ? 

363.  Instead  of  adding  acetic  acid  to  the  dye-bath  for  basic  colors,  what 
other  additions  may  be  made  ?    Are  basic  colors  ever  dyed  at  the  boil  ? 

364.  When  may  the  tannin  mordant  on  cotton  be  fixed  with  iron  in  place 
of  antimony?    What  salts  of  iron  may  be  used?    What  is  the  color  of  iron 
tannate  ? 

365.  In  fixing  tannin  with  an  iron  salt  how  may  acidity  in  the  fixing  bath 
be  neutralized  ?     From  what  does  this  acidity  arise  ? 


148  DYEING  AND   TEXTILE  CHEMISTRY. 

366.  Are  dyeings  on  an  iron-tannin  mordant  as  fast  as  if  antimony  were 
used  for  fixing  ?     How  may  the  process  of  fixing  tannin  with  iron  be  modified 
in  order  to  obtain  faster  dyeings  ? 

367.  What  basic  colors  may  be  applied  to  cotton  without  a  mordant? 
How  is  the  dye-bath  prepared  in  such  a  case  ?    Are  the  colors  fast  ? 

368.  How  may  bright  pinks  be  obtained  on  cotton  with  an  oil  mordant? 
What  oil  is  used?    How  is  the  mordanting  conducted?    How  is  the  dyeing 
carried  out  and  in  what  kind  of  a  bath?    What  precautions  are  necessary  in 
order  to  obtain  level  colors  ? 


SECTION  XIII. 
APPLICATION  OF  SUBSTANTIVE  DYES  TO  COTTON. 

Experiment  82.  General  Method  of  Dyeing  Cotton.  —  These 
dyes  are  usually  applied  to  cotton  in  a  neutral  bath  containing 
either  common-salt  or  glaubersalt;  hence,  the  name  of  "salt" 
or  "direct  cotton"  colors  for  this  class  of  dyes.  Dye  a  skein  of 
cotton  yarn  in  a  bath  containing  300  cc.  of  water,  20  per  cent,  of 
common-salt,  and  i  per  cent,  of  Congo  Red;  enter  at  140°  F., 
gradually  raise  to  the  boil,  and  dye  at  that  temperature  for  one- 
half  hour;  then  wash  well  and  dry  (247).  The  bath  does  not 
exhaust  very  well,  but  by  adding  more  salt  towards  the  end  of  the 
dyeing  a  better  degree  of  exhaustion  may  be  obtained,  although  the 
colors  are  not  apt  to  be  so  fast  to  washing.  The  use  of  the  com- 
mon-salt (or  of  glaubersalt)  in  the  bath  is  to  increase  the  exhaus- 
tion and  give  better  penetration  of  the  color  through  the  fibre. 
The  substantive  dyes  give  good  colors  on  cotton,  many  of  them 
being  fast  to  light,  acids,  and  alkalies,  though  some  of  them  are 
changed  by  treatment  with  acids,  as  is  the  case  with  Congo 
Red.  To  show  this  action,  dip  a  few  strands  of  the  dyed  yarn 
plaited  together  into  a  dilute  solution  of  sulphuric  acid;  it  will  be 
found  that  the  red  color  is  changed  to  a  bluish  black.  The  red 
color  may  be  brought  back  by  treatment  with  alkalies,  which  may 
be  shown  by  dipping  a  portion  of  the  above  sample  in  a  dilute 
solution  of  soda  ash.  Do  this  carefully  and  then  wash  well  so 
that  the  sample  (248)  will  show  one-half  discolored  and  the  other 
half  red.  The  chief  defect  of  the  substantive  dyes  however,  on 
cotton,  is  their  liability  to  bleed  on  washing  in  hot  water  or  soap 
solutions.  To  show  this  action,  make  up  two  plaited  samples 
from  the  dyed  skein  together  with  white  cotton  yarn;  boil  one  of 
these  in  plain  water  for  15  minutes,  then  squeeze  and  dry  (249), 
when  it  will  be  found  that  the  color  has  bled  into  the  white 

149 


150  DYEING   AND    TEXTILE   CHEMISTRY. 

yarn.  Scour  the  other  sample  in  a  warm  dilute  soap  bath,  then 
wash  in  fresh  water  and  dry  (250),  and  note  if  the  color  has 
bled  or  not  into  the  white. 

Experiment  83.  Influence  of  the  Amount  of  Salt  in  the  Dye- 
bath.  —  Dye  skeins  of  cotton  yarn  in  baths  containing  3  per  cent, 
of  Chicago  Blue  and  the  respective  amounts  of  common-salt  as 
given  below;  enter  at  160°  F.,  bring  to  the  boil,  and  dye  at  that 
temperature  for  one-half  hour,  then  wash  well  and  dry  (251,  252, 
253,  254). 

(1)  Use  no  salt.  (3)  Use  20  per  cent,  of  salt. 

(2)  Use  5  per  cent,  of  salt.        (4)  Use  100  per  cent,  of  salt. 

Compare  the  depth  of  color  obtained  on  the  several  skeins  and 
determine  what  influence,  if  any,  the  amount  of  salt  has  on  the 
color  taken  up  by  the  fibre. 

Experiment  84.  Use  of  Soda  Ash.  —  Very  often  a  better  degree 
of  exhaustion  of  the  dye-bath  and  a  greater  fastness  of  the  color 
to  washing  may  be  obtained  by  dyeing  substantive  colors  in  a 
bath  made  slightly  alkaline  with  soda  ash.  Dye  a  skein  of  cotton 
yarn  in  a  bath  containing  20  per  cent,  of  salt,  i  per  cent,  of  soda 
ash,  and  2  per  cent,  of  Columbia  Green;  enter  at  160°  F.,  gradually 
bring  to  the  boil,  and  dye  at  that  temperature  for  one-half  hour. 
Wash  well  and  dry  (255).  In  place  of  using  soda  ash,  which  is 
a  strong  alkali,  milder  alkaline  salts  such  as  sodium  phosphate  or 
sodium  silicate  may  be  used. 

Experiment  85.  Use  of  Soap.  —  This  method  is  somewhat 
similar  to  the  preceding,  except  that  soap  is  used  for  making  the 
bath  alkaline;  it  is  also  supposed  that  this  makes  the  color  some- 
what faster  to  washing  with  soap.  Dye  a  skein  of  cotton  yarn  in 
a  bath  containing  5  per  cent,  of  soap  and  2  per  cent,  of  Columbia 
Green;  enter  at  i6o°F.,  gradually  bring  to  the  boil,  and. dye  at 
that  temperature  for  one-half  hour;  wash  well  and  dry  (256). 
Salt  cannot  be  used  in  the  bath,  as  it  precipitates  the  soap.  For 
comparison  dye  another  skein  of  cotton  yarn  in  a  bath  with 
20  per  cent,  of  salt  and  2  per  cent,  of  Columbia  Green  in  the  usual 


APPLICATION  OF  SUBSTANTIVE  DYES   TO   COTTON.      151 

manner;  wash  well  and  dry  (257).  Compare  the  colors  obtained 
on  these  skeins  with  the  one  in  the  previous  experiment;  also 
test  them  for  fastness  to  washing  and  note  if  the  method  of  dyeing 
in  the  alkaline  or  soap  baths  has  increased  the  fastness  of  the 
color  to  any  extent. 

Experiment  86.  After-treatment  with  Chrome.  —  This  treat- 
ment is  for  the  purpose  of  increasing  the  fastness  of  certain  sub- 
stantive dyes  to  washing  and  acids;  it  also  deepens  the  color,  as 
a  rule,  to  quite  a  degree,  and  in  some  cases  causes  a  considerable 
change  in  the  tone  of  the  color.  Dye  two  skeins  of  cotton  yarn 
together  in  a  bath  containing  20  per  cent,  of  common-salt  and 

2  per  cent,  of  Chromanil  Brown  2G;  enter  at  i6o°F.,  gradually 
raise  to  the  boil,  and  dye  at  that  temperature  for  one-half  hour; 
wash  well,  and  set  one  of  the  skeins  aside  for  comparison  (258). 
Take  the  second  skein  and  pass  into  a  bath  containing  2  per  cent, 
of  chrome;  boil  for  15  minutes,  then  wash  well  and  dry  (259). 
Compare  the  colors  obtained  on  each  of  the  skeins  and  thus  note 
the  effect  of  the  after-chroming  on  the  color.     Make  tests  on 
both  skeins  for  fastness  to  washing  and  perspiration;  also  test  the 
colors  for  their  fastness  to  light. 

Experiment  87.  After-treatment  with  Bluestone.  —  This  treat- 
ment is  usually  for  the  purpose  of  giving  an  increased  fastness 
to  light;  the  color  is  also  generally  considerably  altered  in  tone 
by  the  treatment.  Dye  two  skeins  of  cotton  yarn  together  in  a 
bath  containing  20  per  cent,  of  common-salt  and  2  per  cent,  of 
Diamine  Blue  RW;  enter  at  160°  F.,  gradually  raise  to  the  boil, 
and  dye  at  that  temperature  for  one-half  hour;  wash  well,  and  set 
one  of  the  skeins  aside  for  comparison  (260).  Pass  the  second 
skein  into  a  fresh  bath  containing  3  per  cent,  of  bluestone  and 

3  per  cent,  of  acetic  acid;  work  for  15  minutes  at  a  temperature  of 
i8o°F.,  then  wash  well  and  dry  (261).     Compare  the  color  on 
the  two  skeins,  and  make  a  test  on  each  for  its  fastness  to  light 
(262,  263). 

Experiment  88.  Dyeing  in  a  Cold  Bath.  —  Many  of  the  sub- 
stantive dyes  are  taken  up  by  cotton  from  a  cold  bath  almost 
as  well  as  from  a  hot  bath,  and  these  become  very  useful  in 


152  DYEING  AND    TEXTILE  CHEMISTRY. 

cases  where  it  is  not  desirable  to  employ  a  very  hot  liquor  in  the 
dye-bath.  Dye  five  test-skeins  of  cotton  yarn  with  the  following 
dyestuff s  respectively  in  baths  containing  20  per  cent,  of  co  mmon- 
salt  and  2  per  cent,  of  the  dyestuff,  enter  cold  and  dye  (without 
heating)  for  three-quarters  hour;  then  wash  and  dry  (264,  265,  266, 
267,  268).  It  is  necessary  to  have  the  yarn  very  well  boiled-out 
for  this  method  of  dyeing,  as  otherwise  it  will  be  difficult  to  obtain 
good  penetration  of  the  coloring-matter  into  the  fibre.  It  is  also 
well  to  add  to  the  dye-bath  a  small  amount  of  Turkey-red  oil  in 
order  to  increase  the  penetration.  Use  the  following  dyestuff  s: 

Erika  BN.  Chrysophenine.    1 

Brilliant  Orange  G.          Chicago  Blue6B.l  (Ber.) 
Heliotrope  26. 

For  the  dyeing  of  light  shades  soap  is  often  added  to  the  bath, 
as  this  helps  the  wetting-out  of  the  cotton;  for  heavy  shades, 
besides  Turkey-red  oil,  there  may  also  be  added  a  small  amount 
of  soda  ash  to  give  a  better  exhaustion  of  the  bath. 

Experiment  89.  Shading  Substantive  Dyes  with  Basic  Dyes.  — 
Substantive  dyes  act  as  mordants  toward  basic  dyes,  on  which 
account  the  latter  may  be  employed  for  purposes  of  topping  or 
shading  the  former.  According  to  the  depth  of  the  substantive 
dyeing,  from  }  to  J  per  cent,  of  basic  dye  may  be  fixed  with  con- 
siderable fastness  to  washing.  Almost  any  substantive  dye  may 
be  used  as  the  bottom  color,  and  almost  any  basic  dye  may  be 
employed  for  topping.  The  dyeing  with  the  substantive  color 
is  carried  out  in  the  usual  manner,  while  the  topping  with  the 
basic  color  is  done  in  a  fresh  cold  bath,  either  with  or  without  the 
addition  of  a  small  amount  of  acetic  acid.  The  method  is  used 
for  the  purpose  of  giving  increased  depth  of  color  as  well  as 
increased  brightness;  for  the  substantive  colors,  as  a  rule,  are 
neither  very  intense  nor  very  bright.  In  some  cases  the  fastness 
of  the  color  to  washing  and  light  is  also  increased.  Dye  five  test- 
skeins  of  cotton  yarn  in  the  usual  manner  with  2  per  cent,  of 
Chrysophenine  (269);  wash  well  and  top  the  five  skeins  as 


APPLICATION  OF  SUBSTANTIVE  DYES   TO   COTTON.      153 

follows  in   cold  baths  containing  \  per  cent,  of  the  respective 
dyestuff  s : 

(1)  Methylene  Blue.  (3)  Rhodamine. 

(2)  Methyl  Violet.  (4)  Auramine  O. 

(5)  Malachite  Green. 

Enter  cold  and  dye  at  that  temperature  for  one-half  hour; 
wash  well  and  dry  (270,  271,  272,  273,  274). 

Dye  a  skein  of  cotton  yarn  in  the  usual  manner  with  2  per  cent, 
of  Chicago  Blue  6B;  wash  well  (275)  ]  and  top  as  in  the  foregoing 
test  with  J  per  cent,  of  Methylene  Blue;  wash  well  and  dry  (276). 

Dye  a  skein  of  cotton  yarn  in  the  usual  manner  with  3  per  cent, 
of  Diamine  Scarlet  36;  wash  well  (277),  and  top  as  before  with 
J  per  cent,  of  Rhodamine  (278). 

In  each  case  preserve  a  sample  of  the  skein  dyed  with  the 
substantive  color  alone  and  compare  it  with  the  topped  sample. 

NOTES. 

i.  The  Substantive  Dyestuffs.  —  These  coloring-matters  were 
first  discovered  in  1884  in  the  dyestuff  known  as  Congo  Red  by 
Boettiger.  They  are  distinguished  by  the  common  property  of 
dyeing  the  vegetable  fibres  in  full  and  comparatively  fast  shades 
without  the  intervention  of  mordants;  they  also  dye  the  animal 
fibres,  wool  and  silk.  Their  chief  application,  however,  is  to  cot- 
ton. At  present  there  are  several  distinct  classes  of  substantive 
dyes  as  far  as  their  chemical  constitution  is  concerned,  but  for 
the  most  part  they  are  derived  more  or  less  directly  from  the  parent 
substance  benzidine,  and  are  characterized  by  being  "tetrazo" 
compounds;  that  is  to  say,  their  molecule  contains  the  azo  group 
N  =  N  twice.  As  benzidine  is  a  diamine  compound  (that  is, 
contains  the  diamine  group,  NH2,  twice),  these  colors  are  also 
knowrr  as  the  "dianaine"  colors.  The  nature  of  the  dyeing 
process  with  regard  to  the  substantive  colors  on  cotton  is  not  as 
yet  thoroughly  understood ;  unlike  the  dyeing  of  the  acid  and  basic 
colors,  there  appears  to  be  no  reason  for  assuming  that  a  chemi- 
cal reaction  occurs  between  the  fibre  and  the  dyestuff.  The 
substantive  dyes  as  a  rule  are  very  soluble  in  water,  and  conse- 


154  DYEING  AND    TEXTILE  CHEMISTRY. 

quently  the  dye-baths  are  seldom  completely  exhausted  even 
when  relatively  small  amounts  of  the  coloring-matter  are  used. 
Cotton  which  has  been  dyed  with  a  substantive  color  will  also 
usually  bleed,  or  have  some  of  its  color  extracted  again  when 
boiled  in  fresh  water;  and  this  extraction  of  color  may  be  succes- 
sively repeated  until,  a  large  part  of  the  dyestuff  has  been  removed 
from  the  fibre.  Again,  the  amount  of  coloring-matter  which  can 
be  taken  up  by  the  cotton  fibre  appears  to  be  rather  limited,  on 
which  account  very  heavy,  dense  shades,  as  a  rule,  cannot  be 
obtained  with  the  substantive  colors  on  cotton.  By  the  addition 
of  salt  to  the  dye-bath  the  solubility  of  the  coloring-matter  in  the 
water  is  lessened,  and  consequently  more  of  the  color  is  forced  on 
the  cotton;  this  condition  is  also  favored  by  employing  as  "short" 
a  bath  as  possible,  that  is,  one  containing  a  minimum  amount  of 
dye  liquor.  Either  common-salt  (sodium  chloride)  or  glauber- 
salt  (sodium  sulphate)  may  be  used  in  the  dye-bath,  though  the 
former  is  mostly  used,  as  it  is  anhydrous  and  does  not  require 
such  a  large  amount  to  be  added.  In  common  practice  about 
20  per  cent,  of  salt  is  used  in  the  bath,  though  when  it  is  desired 
to  obtain  heavy  shades  or  to  get  a  better  degree  of  exhaustion 
larger  amounts  of  salt  may  be  used,  even  to  as  high  as  100  per 
cent,  on  the  weight  of  the  cotton  being  dyed.  If  too  great  an 
amount  of  salt  is  added  there  will  be  danger  of  some  of  the  dye- 
stuff  being  precipitated  or  " salted  out";  this,  however,  as  a  rule 
will  not  occur  until  about  i  pound  of  salt  per  gallon  of  solution 
has  been  added,  an  amount  which  will  hardly  ever  be  used  in 
practice.  When  the  dye  liquor,  however,  is  employed  as  a  stand- 
ing bath,  care  must  be  had  that  in  the  successive  additions  of 
dyestuffs  and  salt  the  accumulation  of  the  latter  in  the  bath 
does  not  become  too  great.  In  order  to  control  this  amount  the 
density  of  the  liquor  should  be  determined  with  a  hydrometer. 
For  light  shades,  as  a  rule,  but  little  salt  is  used,  and  as  only  a 
slight  proportion  of  color  remains  in  the  bath,  the  liquors  are 
seldom  kept  for  further  use.  For  medium  shades  the  best  density 
of  the  dye  liquor  is  about  2°  Tw.,  and  for  dark  shades  from  4  to 
6°  Tw.  In  determining  the  density  of  the  liquor  with  the  hydrom- 


APPLICATION  OF  SUBSTANTIVE  DYES   TO   COTTON.      155 

eter,  a  small  portion  should  be  taken  from  the  vat  and  allowed 
to  cool  before  being  tested.  When  dyeing  in  baths  containing 
a  large  amount  of  salt,  it  is  best  not  to  add  the  salt  until  towards 
the  end  of  the  operation,  and  the  goods  after  coming  from  the 
dye-bath  should  be  well  rinsed  in  fresh  water,  otherwise  the  salt 
may  crystallize  in  the  material  and  afterwards  be  more  difficult  to 
remove.  Increased  exhaustion  of  the  dye-bath  may  also  be 
obtained  by  using  vats  heated  with  closed  steam  coils,  as  the 
introduction  of  live  steam  into  the  bath  considerably  dilutes  it. 
Increased  exhaustion  is  also  obtained  by  allowing  the  color  to 
feed  on  the  cotton  from  a  cooling  bath;  that  is  to  say,  the  cotton 
should  not  be  taken  from  the  bath  at  a  boil,  but  the  steam  should 
be  turned  off  and  the  bath  allowed  to  cool  down  with  the  cotton 
in  it.  As  the  substantive  colors  are  so  soluble  in  water  and 
exhaust  so  poorly,  it  will  seldom  occur  that  they  will  dye  unevenly; 
if  such,  however,  does  happen,  they  may  be  easily  levelled  by 
continued  working  in  a  boiling  bath. 

Many  of  the  substantive  dyes  appear  to  work  somewhat  better 
when  the  bath  is  made  slightly  alkaline  by  the  addition  of  soda 
ash,  sodium  phosphate,  sodium  silicate,  borax,  soap,  etc.  Just  what 
is  the  action  of  the  alkali  in  this  case  is  uncertain;  it  probably  aids 
in  the  penetration  of  the  coloring-matter  into  the  fibre.  For  light 
shades  it  is  sometimes  beneficial  to  add  Turkey-red  oil  to  the  bath. 
In  preparing  the  dye-bath  in  practice,  it  is  best  to  first  add  the 
alkali  (if  such  is  used) ,  then  the  color  solution,  and  finally  the  salt. 

The  substantive  colors  should  be  dissolved  in  boiling  water, 
and  if  possible,  water  from  condensed  steam  should  be  used.  If 
the  water  to  be  used  for  dissolving  the  dyestuff  is  calcareous,  it  is 
best  to  first  boil  the  water  up  with  an  amount  of  soda  ash  equiva- 
lent to  the  weight  of  the  dyestuff  to  be  dissolved.  After  dis- 
solving the  color,  the  solution  should  be  strained  through  a  piece 
of  cotton  cloth  or  fine  sieve.  When  the  dyestuff  is  added  in  an 
undissolved  condition  directly  to  the  dye-bath,  some  soda  ash 
should  first  be  added,  the  bath  boiled  up,  and  then  the  dyestuff 
added,  after  which  the  salt  is  added. 

Where  hard  water  must  be  used  in  dyeing  substantive  colors 


156  DYEING   AND    TEXTILE   CHEMISTRY. 

it  should  always  first  be  corrected  by  treatment  with  a  suitable 
amount  of  soda  ash.  With  certain  colors  which  are  especially 
sensitive  to  hard  water,  it  is  recommended  to  dye  with  addition 
of  2  to  4  per  cent,  of  acid  potassium  oxalate,  the  amount  depending 
on  the  hardness  of  the  water  and  the  quantity  of  dyestuff  to  be 
used;  it  should  be  noted ^that  an  excess  of  the  oxalate  is  injurious, 
causing  the  color  to  exhaust  badly  and  giving  dull  shades. 

It  is  a  mistake  to  suppose  that  the  substantive  dyes  require  a 
vigorously  boiling  bath  for  dyeing;  while  it  is  true  that  a  boiling 
bath  will  give  a  better  penetration  of  color,  it  is  also  a  fact  that 
the  amount  of  color  absorbed  by  the  cotton  is  greater  when  the 
temperature  of  the  bath  is  under  the  boil,  and  it  has  already  been 
pointed  out  that  a  better  degree  of  exhaustion  is  obtained  by 
allowing  the  goods  to  remain  for  some  time  in  the  cooling  bath. 
When  desirable,  most  of  the  substantive  colors  may  be  dyed  at 
moderate  temperatures,  and  even  cold.  In  such  cases  it  is  best 
to  add  to  the  bath  some  soap  or  Turkey-red  oil  in  order  to  obtain 
better  penetration  of  the  coloring-matter.  When  dyeing  in  a  cold 
bath  it  is  sometimes  recommended  to  mix  the  dyestuff  first  with 
its  own  weight  of  caustic  soda  solution  (78°  Tw.),  then  dissolve  in 
a  sufficient  quantity  of  hot  water,  and  add  this  solution  to  the  dye- 
bath  along  with  a  little  soap. 

For  dyeing  light  shades  for  each  100  pounds  of  cotton  yarn 
about  200  gallons  of  water  should  be  used,  while  for  dark  shades 
the  amount  of  water  should  be  limited  to  about  130  gallons.  For 
dark  shades,  especially  where  only  one  dyestuff  is  used  in  the 
color,  the  yarn  can  usually  be  entered  at  the  boil;  for  lighter 
shades,  and  where  several  dyes  may  be  used  in  combination,  it  is 
best  to  enter  the  cotton  at  140  to  160°  F.,  and  gradually  raise  to 
the  boil.  If  any  tendency  towards  unevenness  is  observed,  it  is 
best  to  add  only  a  part  of  the  salt  to  the  bath  at  first  and  reserve 
the  rest  to  be  added  near  the  end  of  the  dyeing.  Yarn  which  has 
been  dyed  in  light  shades  is  not  generally  rinsed  after  dyeing 
unless  alkali  has  been  used  in  the  bath;  but  where  heavy  shades 
are  obtained  the  yarn  should  always  be  well  rinsed  in  order  to 
remove  all  excess  of  residual  dye  liquor  and  salt  solution. 


APPLICATION  OF  SUBSTANTIVE  DYES   TO   COTTON.      157 

SAMPLES. 

247.  Congo  Red  on  cotton,  showing  method  of  dyeing. 

248.  Congo  Red  tested  with  acid  and  alkali. 

249.  Congo  Red  tested  for  bleeding. 

250.  Congo  Red  tested  for  fastness  to  washing. 

251.  Chicago  Blue  dyed  with  no  salt. 

252.  Chicago  Blue  dyed  with  5  per  cent.  salt. 

253.  Chicago  Blue  dyed  with  20  per  cent.  salt. 

254.  Chicago  Blue  dyed  with  100  per  cent.  salt. 

255.  Columbia  Green  dyed  with  soda  ash. 

256.  Columbia  Green  dyed  with  soap. 

257.  Columbia  Green  dyed  with  salt  alone. 

258.  Chromanil  Brown  before  treatment. 

259.  Chromanil  Brown  treated  with  chrome. 

260.  Diamine  Blue  RW  before  treatment. 

261.  Diamine  Blue  RW  treated  with  bluestone. 

262.  Untreated  sample  exposed  to  light. 

263.  Treated  sample  exposed  to  light. 

264.  Erika  BN  dyed  in  a  cold  bath. 

265.  Brilliant  Orange  G  dyed  in  a  cold  bath. 

266.  Chrysophenine  dyed  in  a  cold  bath. 

267.  Chicago  Blue  6B  dyed  in  a  cold  bath. 

268.  Heliotrope  26  dyed  in  a  cold  bath. 

269.  Chrysophenine  (2  per  cent.)  as  a  bottom  color. 

270.  Topped  with  Methylene  Blue. 

271.  Topped  with  Methyl  Violet. 

272.  Topped  with  Rhodamine. 

273.  Topped  with  Auramine. 

274.  Topped  with  Malachite  Green. 

275.  Chicago  Blue  6B  as  a  bottom  color. 

276.  Topped  with  Methylene  Blue. 

277.  Diamine  Scarlet  36  as  a  bottom  color. 

278.  Topped  with  Rhodamine. 

QUIZ  13. 

369.  In  what  character  of  bath  are  the  substantive  colors  usually  applied 
to  cotton?  Why  are  these  dyes  sometimes  called  "salt"  or  "direct  cotton" 
colors  ? 

3  70 .  Does  the  dye-bath  with  Congo  Red  exhaust  well  ?  How  may  the  degree 
of  exhaustion  be  influenced  ?  In  the  latter  case  are  the  colors  obtained  as  fast  ? 

371.  What  is  the  function  of  the  common-salt  in  the  dye-bath  when  using 
substantive  colors?  What  other  neutral  salt  may  be  used? 


158  DYEING  AND    TEXTILE  CHEMISTRY. 

372 .  What  is  the  general  fastness  of  the  substantive  dyes  on  cotton  ?    What 
is  their  chief  defect  ? 

373.  What  takes  place  when  the  color  obtained  with  Congo  Red  is  treated 
with  acid  ?    And  subsequently  treated  with  soda  ash  ? 

374.  Was  the  dyeing  with  Congo  Red  fast  to  bleeding  and  to  the  washing 
test  ?    How  were  these  tests  made  ? 

375.  What  do  you  consider  the  influence  of  varying  amounts  of  salt  in  the 
bath  in  dyeing  substantive  colors  on  cotton  ? 

376.  Why  is  soda  ash  used  at  times  in  dyeing  substantive  colors?    What 
other  alkalies  in  place  of  soda  ash  may  be  used  ? 

377.  Why  is  it  recommended  at  times  to  add  soap  to  the  dye-bath  with 
substantive  colors?    How  much  soap  is  used?     Can  salt  be  used  in  such  a 
bath,  and  why? 

378.  What  is  the  purpose  of  after-treating  certain  substantive  colors  with 
chrome  ?    What  effect  has  the  process  on  the  tone  of  the  color  ? 

379.  How  is  the  after-treatment  with  chrome  carried  out  ?    What  difference 
did  you  find  in  the  fastness  to  washing,  perspiration,  and  light  between  the 
treated  and  the  untreated  dyeings  ?    How  did  you  conduct  these  tests  ? 

380.  What  is  the  purpose  of  after-treating  some  substantive  colors  with 
bluestone?     How  is  the  process  conducted?    What  effect  has  the  treatment 
on  the  tone  of  the  color?    Did  you  find  any  marked  difference  in  the  fastness 
to  light  of  the  two  samples  tested  ? 

381.  Can  substantive  dyes  be  applied  to  cotton  in  a  cold  bath?     How  is 
this  done?    Why  is  Turkey-red  oil  added  and  why  should  the  yarn  be  well 
boiled  out  ? 

382.  For  dyeing  light  shades  in  a  cold  bath  what  addition  may  be  made  to 
the  bath  ?    For  heavy  shades  what  additions  are  made  ? 

383.  What  color  does  the  dyestuff  Erica  give?   What  color  does  Chrysoph- 
enine  give  ? 

384.  How  do  substantive  dyes  act  towards  basic  dyes?    What  is  meant  by 
"  topping"  a  color? 

385.  How  much  basic  color  may  be  fixed  on  a  substantive  dyeing?    How 
is  the  topping  with  the  basic  color  carried  out  ? 

386.  What  is  the  purpose  of  topping  a  substantive  dyeing  with  a  basic  color  ? 
Describe  the  results  you  obtained  on  topping  Chrysophenine  with  various  basic 
colors. 

387.  What  is  the  effect  of  topping  Chicago  Blue  with  Methylene  Blue  ?     Of 
topping  Diamine  Scarlet  with  Rhodamine  ? 

388.  When  were  the  substantive  dyes  first  introduced  and  by  whom  ?    What 
was  the  first  dye  discovered  ? 

389.  What  is  the  distinguishing  characteristic  of  the  substantive  dyes  as  a 
class  ?    To  what  fibre  are  they  chiefly  applied  ? 


APPLICATION  OF  SUBSTANTIVE  DYES   TO   COTTON.      159 

390.  From  what  parent  substance  are  most  of  the  substantive  dyes  derived? 
By  what  chemical  group  are  they  characterized  ? 

391.  What  is  meant  by  a  "tetrazo"  compound?     By  a  "diamine"? 

392.  Is  the  nature  of  the  dyeing  process  with  substantive  colors  well  under- 
stood ?     How  does  it  differ  from  that  of  the  acid  and  basic  dyes  ? 

393-  What  may  be  said  as  to  the  solubility  of  the  substantive  dyes?  How 
does  this  affect  their  exhaustion  from  the  dye-bath?  Why  do  their  colors 
usually  bleed  from  cotton  when  steeped  or  boiled  in  water  ? 

394.  Can  very  heavy  shades  be  obtained  on  cotton  with  the  substantive 
dyes?    Why? 

395.  What  conditions  favor  a  better  degree  of  exhaustion  of  the  substantive 
dye-bath? 

396.  What  is  the  danger  of  adding  too  great  an  amount  of  salt  to  the  bath 
with  substantive  colors  ?    What  is  the  maximum  amount  of  salt  which  should 
ever  be  added  ? 

397.  In  using  standing  baths  with  substantive  dyes  how  is  the  concentration 
of  the  liquor  controlled?    What  should  be  the  density  for  light  shades;  for 
heavy  shades  ? 

398.  When  dyeing  in  baths  containing  a  large  amount  of  salt  why  should 
the  goods  be  well  washed  immediately  after  coming  from  the  bath  ? 

399.  In  what  manner  should  dye-vats  be  heated  if  it  is  desired  to  keep  the 
liquor  concentrated? 

400.  What  is  the  effect  of  allowing  the  cotton  to  remain  in  the  cooling  bath 
when  dyeing  with  the  substantive  colors  ? 

401.  Are  the  substantive  colors  liable  to  dye  unevenly?    Why?    If  uneven, 
how  may  the  color  be  levelled  ? 

402.  What  is  the  object  of  dyeing  some  substantive  colors  in  an  alkaline 
bath  ?    What  alkalies  may  be  employed  ?    What  is  the  probable  action  of  the 
alkali? 

403.  When  dyeing  substantive  colors  with  an  alkaline  bath  in  what  order 
should  the  various  additions  to  the  bath  be  made  ? 

404.  In  dyeing  light  shades  with  the  substantive  colors  what  addition  to  the 
bath  is  beneficial  ? 

405.  In  what  manner  should  the  substantive  colors  be  dissolved?     Should 
hard  water  be  employed  for  this  purpose  ? 

406.  What  is  meant  by  "calcareous"  water?     How  may  this  water  be 
corrected  for  use  with  the  substantive  dyes  ? 

407.  When  substantive  colors  are  added  directly  to  the  dye-bath  how  should 
the  preparation  of  the  bath  be  effected  ? 

408.  Some  substantive  dyes  are  very  sensitive  to  hard  water;  what  addition 
should  be  made  to  the  dye-bath  in  such  a  case  ?   Explain  how  this  will  neutralize 
the  hardness  of  the  water.     Why  is  an  excess  of  the  chemical  detrimental  ? 


160  DYEING  AND    TEXTILE  CHEMISTRY. 

409.  Do  substantive  colors  require  a  vigorous  boiling  in  dyeing?    What 
purpose  does  the  boiling  effect  ?    Under  what  conditions  is  the  greatest  amount 
of  color  absorbed  ? 

410.  May  substantive  colors  be  dyed  in  a  cold  bath?    What  additions  to 
the  bath  should  be  made  and  for  what  purpose  ? 

411.  What  method  is  recommended  for  dissolving  the  dyestuff  when  using 
substantive  colors  in  a  cold  bath  ? 

412.  In  dyeing  light  shades  with  substantive  colors  how  many  gallons  of 
water  should  be  used  for  100  pounds  of  cotton?     How  many  gallons  when 
dyeing  dark  shades? 

413.  When  dyeing  heavy  shades  with  a  single  substantive  dye  on  cotton  at 
what  temperature  may  the  goods  be  entered  in  the  bath  ?    What  temperature 
is  best  when  light  shades  or  compound  colors  are  being  dyed  ? 

414.  If  in  dyeing  substantive  colors  the  shades  come  up  uneven  what  is  the 
best  procedure  to  adopt  to  obtain  level  colors? 

415.  After  cotton  is  dyed  with  substantive  colors  should  it  be  washed? 
Under  what  conditions  may  the  washing  be  dispensed  with  ? 


SECTION  XIV. 
SUBSTANTIVE  DYES  ON  WOOL  AND  SILK. 

Experiment  90.  General  Method  of  Dyeing  Wool.  —  These 
colors  are  usually  dyed  on  wool  in  a  neutral  bath  containing  either 
glaubersalt  or  common-salt.  Although  the  substantive  colors  are 
primarily  dyes  for  use  on  cotton,  nevertheless,  they  are  being 
employed  to  a  considerable  extent  on  wool,  as  many  of  them  give 
colors  of  eminent  fastness.  Dye  a  skein  of  woolen  yarn  in  a  bath 
containing  20  per  cent,  of  glaubersalt  and  3  per  cent,  of  Diamine 
Scarlet  36.  Enter  at  140°  F.,  gradually  bring  to  the  boil,  and 
dye  at  that  temperature  for  one-half  hour,  then  wash  well  and 
dry  (279).  Common-salt  may  be  used  in  the  bath  in  place  of 
glaubersalt  and  has  the  same  effect.  The  purpose  of  the  addition 
of  these  neutral  salts  is  to  cause  a  better  penetration  and  distribu- 
tion of  the  coloring-matter,  and  also  to  cause  a  better  exhaustion 
of  the  dye-bath.  The  substantive  dyes,  as  a  rule,  are  very  soluble 
in  water,  and  show  no  particular  tendency  to  go  on  the  fibre 
unevenly,  hence  the  material  may  be  entered  at  comparatively 
high  temperatures  without  the  danger  of  unevenness.  Also  due 
to  its  good  solubility  in  water,  the  dyestuff  does  not  give  complete 
exhaustion  in  the  bath.  The  substantive  dyes  do  not  produce  as 
bright  or  as  full  shades  on  wool  as  the  basic  and  acid  dyes.  Some 
of  the  substantive  dyes,  especially  the  reds,  are  very  sensitive  to 
the  action  of  acids,  their  color  being  changed,  as  has  been  shown 
in  the  previous  section,  with  Congo  Red.  The  dyestuff  used  above, 
however,  is  fast  to  acid,  as  may  be  shown  by  moistening  a  small 
sample  of  the  dyed  yarn  with  a  dilute  solution  of  sulphuric  acid, 
washing  and  drying  (280).  Also  test  this  color  for  its  fastness  to 
fulling  (281). 

Experiment  91.    Use  of  Ammonium  Acetate  in  the  Dye-bath.  — 
The  use  of  this  salt  in  the  dye-bath  appears  to  give  better  exhaus- 

161 


1 62  DYEING   AND    TEXTILE   CHEMISTRY. 

tion  and  also  to  make  the  color  faster  to  fulling.  Dye  a  skein  of 
woolen  yarn  in  a  bath  containing  5  per  cent,  of  ammonium  acetate 
and  3  per  cent,  of  Diamine  Green  G;  enter  at  140°  F.,  gradually 
raise  to  the  boil,  and  dye  at  that  temperature  for  one-half  hour. 
Wash  and  dry  (282).  The  ammonium  acetate,  on  boiling, 
decomposes  into  ammonia  (which  is  volatilized)  and  free  acetic 
acid,  and  this  no  doubt  helps  in  the  dyeing  of  the  wool.  Ammo- 
nium acetate  may  be  readily  prepared  by  mixing  ammonia  water 
and  acetic  acid  in  the  following  proportions:  32  parts  of  strong 
ammonia  water  and  50  parts  of  acetic  acid  (1.031  sp.  gr.)  which 
will  give  a  solution  containing  25  parts  of  ammonium  acetate. 
Diamine  Green  gives  a  color  on  wool  which  has  good  fastness  to 
washing. 

Experiment  92.  Dyeing  in  a  Slightly  Acid  Bath.  —  Some  of  the 
substantive  dyes  may  be  applied  to  wool  in  slightly  acid  baths 
in  much  the  same  manner  as  the  acid  dyes.  This  method  is 
especially  useful  for  the  production  of  two-color  effects  on  mixtures 
containing  wool  and  cotton.  Dye  a  skein  of  woolen  yarn  in  a 
bath  containing  20  per  cent,  of  glaubersalt,  4  per  cent,  of  acetic 
acid,  and  2  percent,  of  Chrysophenine;  enter  at  140°  F.,  gradually 
raise  to  the  boil,  and  dye  at  that  temperature  for  one-half  hour; 
wash  and  dry  (283).  Acetic  acid  is  mostly  used  in  this  connec- 
tion, as  sulphuric  acid  is  too  strong  and  is  liable  to  injure  the 
color,  and  where  cotton  is  present  there  is  danger  of  the  latter 
fibre  being  tendered  by  the  incomplete  removal  of  the  acid, 
whereas  acetic  acid,  being  volatile,  is  easily  removed.  Chrysoph- 
enine gives  a  good  yellow  color  on  wool  which  is  exceedingly 
fast  to  light;  to  show  this  expose  a  sample  to  light  for  30  days 
(284). 

Experiment  93.  Showing  the  Application  of  Substantive  Dyes 
on  Union  Material.  —  Dye  a  skein  of  union  yarn  (containing  wool 
and  cotton  threads  twisted  together)  in  a  bath  containing  20  per 
cent,  of  glaubersalt,  4  per  cent,  of  acetic  acid,  and  2  per  cent,  of 
Chrysophenine;  enter  at  140°  F.,  gradually  raise  to  the  boil,  and 
dye  at  that  temperature  for  one-half  hour;  wash  well  and  dry 
(285).  It  will  be  found  that  both  fibres  will  be  dyed  about  a 


SUBSTANTIVE  DYES  ON   WOOL  AND   SILK.  163 

uniform  color.  Dye  a  second  skein  of  union  yarn  in  a  bath  con- 
taining 20  per  cent,  of  glaubersalt,  4  per  cent,  of  acetic  acid,  2  per 
cent,  of  Chrysophenine  and  i  per  cent,  of  Acid  Violet.  Dye  in 
the  usual  manner,  wash  well,  and  dry  (286).  It  will  be  found 
in  this  case  that  the  wool  has  been  dyed  with  both  the  yellow  and 
violet  colors,  giving  a  resultant  olive  green,  whereas  the  cotton 
has  been  dyed  with  the  yellow  and  has  only  been  slightly  tinted 
with  the  violet,  so  that  a  two-color  effect  has  been  obtained. 

Experiment  94.  After-treatment  with  Chrome.  —  This  treat- 
ment is  for  the  purpose  of  increasing  the  fastness  of  the  color 
to  washing  and  light.  At  the  same  time  it  also  causes  an  increase 
in  the  depth  of  the  color.  Dye  two  test-skeins  of  woolen  yarn  in 
a  bath  containing  20  per  cent,  of  glaubersalt,  10  per  cent,  of  ammo- 
nium acetate,  and  3  per  cent,  of  Diamine  Fast  Red  F;  enter  at  140° 
F.,  gradually  raise  to  the  boil,  and  dye  at  that  temperature  for  one- 
half  hour.  Remove  one  of  the  skeins,  wash,  and  dry  (287). 
Add  to  the  dye-bath  2  per  cent,  of  chrome,  reenter  the  second 
skein  and  continue  boiling  for  20  minutes;  then  wash  and  dry 
(288).  Compare  the  colors  obtained  on  these  two  samples,  and 
test  each  skein  for  its  fastness  to  washing  (289,  290). 

Experiment  95.  After-treatment  with  Chromium  Fluoride.  - 
This  salt  is  sometimes  substituted  for  chrome.  It  acts  in  much 
the  same  manner  by  increasing  the  fastness  of  certain  colors  to 
light  and  washing,  and  also  deepening  the  shade.  As  it  is  not  a 
strong  oxidizing  agent  like  chrome,  it  may  be  used  at  times  where 
the  latter  cannot.  Dye  two  test-skeins  of  woolen  yarn  in  a  bath 
containing  20  per  cent,  of  glaubersalt  and  3  per  cent,  of  Columbia 
Green;  enter  at  140°  F.,  gradually  raise  to  the  boil,  and  dye  at 
that  temperature  for  one-half  hour.  Remove  one  of  the  skeins, 
and  wash  and  dry  (291).  Add  to  the  dye-bath  3  per  cent,  of  chro- 
mium fluoride,  reenter  the  second  skein  and  boil  for  20  minutes 
longer;  then  wash  and  dry  (292).  Compare  the  two  skeins  with 
respect  to  their  color  and  make  tests  on  each  to  determine  the 
fastness  to  washing  (293,  294). 

Experiment  96.  Example  of  a  Substantive  Dye  not  Coloring 
Wool.  —  There  are  a  few  of  the  substantive  dyes  which  are  not 


1 64  DYEING  AND    TEXTILE   CHEMISTRY. 

taken  up  by  the  wool  fibre,  especially  if  the  bath  is  at  a  compara- 
tively low  temperature  and  is  slightly  alkaline.  Dye  a  test-skein 
of  woolen  yarn  in  a  bath  containing  20  per  cent,  of  glaubersalt, 
i  per  cent,  of  soda  ash,  and  2  per  cent,  of  Mikado  Yellow; 
enter  at  100°  F.,  gradually  raise  to  120°  F.,  and  dye  at  that 
temperature  for  one-half  hour;  then  wash  well  and  dry  (295). 
It  will  be  found  that  the  wool  is  hardly  tinted  by  this 
color.  On  this  account,  such  dyes  are  very  useful  for  the 
dyeing  of  union  materials  where  it  is  desirable  to  leave  the  wool 
undyed. 

Experiment  97.  General  Method  of  Applying  Substantive  Dyes 
to  Silk.  —  This  fibre,  like  wool,  will  dye  very  readily  with  many 
of  the  substantive  colors,  yielding  shades  which  are  fast  to  washing 
and  water  and  in  many  cases  fast  to  light.  Dye  a  skein  of  silk 
in  a  bath  containing  10  per  cent,  of  soap  (or  a  boiled-off  liquor 
bath  may  be  employed  where  this  is  available)  and  3  per  cent,  of 
Benzo  Fast  Scarlet;  enter  at  140°  F.,  gradually  raise  to  the  boil, 
and  dye  at  that  temperature  for  one-half  hour.  Wash  well  and  dry 
(296).  Silk  may  also  be  dyed  in  a  slightly  acid  bath,  as  with 
wool.  Dye  a  skein  of  silk  in  a  bath  containing  3  per  cent,  of 
Chrysophenine,  10  per  cent,  of  glaubersalt,  and  4  per  cent,  of  acetic 
acid;  enter  at  140°  F.,  bring  to  180°  F.,  and  dye  at  that  tempera- 
ture for  one-half  hour.  Wash  well  and  dry  (297).  As  with 
wool,  silk  dyed  with  the  substantive  colors  may  be  after-treated 
with  chrome,  etc.,  in  order  to  obtain  faster  shades.  The  sub- 
stantive colors  are  also  very  useful  in  the  dyeing  of  half-silk 
(silk  and  cotton  fabrics),  both  for  single  colors  and  for  the  produc- 
tion of  two-color  effects,  in  the  same  manner  as  already  described 
under  their  application  to  wool. 

NOTES. 

i.  The  Substantive  Colors  on  Wool.  —  These  dyes  have  gained 
considerable  favor  in  various  branches  of  wool  dyeing,  especially 
for  knitting  yarns  fast  to  washing,  carded  wool  and  worsted  yarns 
fast  to  milling,  shoddy  yarns,  loose  wool,  and  also  for  the  dyeing 
of  slubbing  and  yarns  in  machines.  For  the  latter  they  are 


SUBSTANTIVE  DYES  ON   WOOL   AND   SILK.  165 

especially  adapted  owing  to  their  great  solubility  in  water. 
The  chief  recommendation  of  these  dyes  to  wool  is  their  good 
fastness  to  washing,  and  in  many  cases  excellent  fastness  to 
milling.  This  is  especially  true  of  the  after-treated  dyeings. 
Most  of  the  substantive  colors  are  also  fast  to  stoving.  The  fast- 
ness of  the  substantive  colors  to  washing  is  as  a  rule  much  better 
on  wool  than  it  is  on  cotton.  The  exhaustion  of  the  bath  is  also 
generally  better  when  wool  is  dyed.  The  after-treatment  of  the 
substantive  colors  on  wool  with  chrome  or  chromium  fluoride  is 
usually  carried  out  by  adding  the  salts  to  the  exhausted  dye-bath, 
and  using  about  one-half  the  weight  of  chrome  as  dyestuff  or 
about  the  same  weight  of  chromium  fluoride  as  dyestuff.  The 
dyeings  may  also  be  after-treated  with  bluestone  in  the  same 
manner  as  with  chrome,  about  the  same  weight  of  bluestone  as 
dyestuff  being  taken.  An  after-treatment  with  both  chrome  and 
bluestone  may  be  simultaneously  effected  in  the  same  manner. 
In  order  to  obtain  a  better  exhaustion  of  the  dye-bath  for  after- 
treatment  it  is  best  to  add  about  3  to  5  per  cent,  of  acetic  acid  to 
the  bath  in  finishing  the  dyeing;  in  case  the  bath  does  not  exhaust 
well,  it  is  best  to  carry  out  the  after-treatment  in  a  separate  bath 
with  the  addition  of  4  per  cent,  of  acetic  acid. 

It  should  be  observed  that  in  dyeing  wool  with  the  substantive 
colors,  neutral  baths,  or  such  as  are  but  slightly  acidulated  with 
acetic  acid,  with  few  exceptions,  are  the  most  serviceable.  If  the 
baths  are  made  too  strongly  acid,  the  color  is  taken  up  too  rapidly 
by  the  wool,  and  uneven  dyeings  may  result,  which  cannot  after- 
wards be  improved,  even  by  prolonged  boiling.  In  the  case  of 
material  which  is  difficult  to  dye  level,  or  if  compound  shades 
are  not  readily  obtained,  it  is  best  to  begin  the  dyeing  without  the 
addition  of  acid,  and  only  when  the  greater  part  of  the  color  has 
been  taken  up  should  the  acid  be  added  to  the  bath  in  order  to 
increase  the  exhaustion.  It  should  also  be  borne  in  mind  that 
any  vegetable  matter  present  in  the  wool  is  not  dyed  so  much  in 
an  acid  bath  as  in  a  neutral  one.  Substantive  dyes  on  wool 
after- treated  with  bluestone  retain  their  remarkable  fastness  to 
light  even  after  fulling,  provided  a  neutral  curd  soap  is  used; 


1 66  DYEING   AND    TEXTILE   CHEMISTRY. 

free  alkali  (which  is  generally  present  in  soft  soap)  should  never 
be  present  in  the  soap  used  under  these  circumstances. 

2.  The  Substantive  Colors  on  Silk.  —  As  the  majority  of  these 
colors  may  be  dyed  on  silk,  giving  shades  of  considerable  fastness 
to  washing  and  water  as  well  as  to  light,  they  are  of  consid- 
erable importance  in  this  branch  of  dyeing.  They  are  also  useful 
for  such  goods  that  may  be  subjected  to  severe  treatment  with  alka- 
lies, such  as  fancy  silk  threads  running  through  cotton  or  woolen 
fabrics.  The  substantive  colors  are  best  dyed  on  silk  with  the 
addition  of  glaubersalt  and  acetic  acid,  or  in  a  bath  containing 
boiled-off  liquor.  If  the  dyeing  is  done  without  the  latter,  add 
to  the  bath  for  pale  shades  about  5  per  cent,  and  for  heavy  shades 
about  10  per  cent,  of  glaubersalt,  and  only  a  small  quantity  (from 
i  to  4  per  cent.)  of  acetic  acid  at  the  beginning  of  the  operation. 
If  the  color  goes  on  the  fibre  too  slowly,  a  little  more  acetic  acid 
may  be  gradually  added  during  the  dyeing  process.  This  pre- 
caution is  necessary  because  it  is  difficult  to  obtain  level  colors 
if  the  bath  is  too  acid  at  the  beginning.  For  the  same  reason  it 
is  also  important  not  to  start  the  dyeing  at  too  high  a  temperature. 
It  is  best  to  commence  at  120°  F.  and  slowly  raise  to  the  boil. 
For  shading  let  the  bath  cool  to  140°  to  160°  F.,  then  add  the 
necessary  color  solution  and  gradually  heat  up  again.  When 
dyeing  light  colors  the  baths  exhaust,  as  a  rule,  with  the  addition 
of  glaubersalt  only,  or  with  a  very  little  acetic  acid  added.  For 
heavy  shades  the  addition  of  2  to  10  per  cent,  of  acetic  acid  is  neces- 
sary. When  dyeing  in  a  bath  containing  boiled-off  liquor,  for 
light  shades  the  liquor  need  only  be  slightly  acid,  but  for  heavy 
shades  the  acidity  should  be  greater.  The  brightening  after 
dyeing  may  be  done  with  either  acetic  or  sulphuric  acid,  and  the 
dyeings  may  be  shaded  in  this  bath  in  any  desired  manner.  The 
fastness  of  the  substantive  colors  on  silk  to  acids,  alkalies,  stoving, 
and  light  corresponds  in  general  to  that  which  they  possess 
when  dyed  on  wool. 


SUBSTANTIVE  DYES  ON   WOOL  AND  SILK.  1 6? 

SAMPLES. 

279.  Diamine  Scarlet  on  wool;  general  method  for  dyeing. 

280.  Acid  test  on  Diamine  Scarlet. 

281.  Fulling  test  on  Diamine  Scarlet. 

282.  Showing  use  of  ammonium  acetate  with  Diamine  Green. 

283.  Chrysophenine  dyed  in  slightly  acid  bath. 

284.  Light  test  on  Chrysophenine. 

285.  Union  yarn  dyed  with  Chrysophenine. 

286.  Union  yarn  dyed  with  Chrysophenine  and  Acid  Violet. 

287.  Diamine  Fast  Red  before  treatment  with  chrome. 

288.  Diamine  Fast  Red  after  treatment  with  chrome. 

289.  Untreated  dyeing  tested  to  washing. 

290.  Chromed  dyeing  tested  to  washing. 

291.  Columbia  Green  before  treatment  with  chromium  fluoride. 

292.  Columbia  Green  after  treatment  with  chromium  fluoride. 

293.  Untreated  dyeing  tested  to  washing. 

294.  Treated  dyeing  tested  to  washing. 

295.  Showing  Mikado  Yellow  does  not  dye  wool. 

296.  Silk  dyed  with  Benzo  Fast  Scarlet  in  soap  bath. 

297.  Chrysophenine  on  silk;  glaubersalt  and  acetic  acid  bath. 

QUIZ  14. 

416.  What  is  the  general  method  of  dyeing  wool  with  the  substantive  colors? 
Are  these  dyes  used  to  any  extent  on  wool  ?    Do  they  yield  fast  colors  ? 

417.  What  is  the  purpose  of  the  addition  of  salt  to  the  dye-bath  with  sub- 
stantive colors  on  wool  ?    What  salts  may  be  used  ? 

418.  Do  the  substantive  dyes  on  wool  show  a  tendency  to  uneven  shades? 
Why? 

419.  How  do  the  colors  with  the  substantive  dyes  on  wool  compare  with 
the  acid  and  basic  dyes  as  to  brightness  and  depth  of  color  ? 

420.  How  does  Diamine  Scarlet  differ  from  Congo  Red  when  tested  with 
acid  ?    Is  this  color  fast  to  fulling  ?    How  is  this  test  conducted  ? 

42 1 .  For  what  purpose  is  ammonium  acetate  added  to  the  bath  when  dyeing 
substantive  colors  on  wool  ?     Give  the  method  of  dyeing  when  using  this  salt. 

422.  What  is  probably  formed  when  the  ammonium  acetate  is  boiled  in  the 
dye-bath? 

423.  How  may  the  solution  of  ammonium  acetate  be  prepared?     How 
would  you  prepare  one  litre  of  a  solution  of  ammonium  acetate  so  that  10  cc. 
would  contain  10  per  cent,  of  the  salt  on  5  grams? 

424.  How  would  you  prepare  a  solution  of  ammonium  acetate  so  that  one 
quart  would  be  equivalent  to  i  per  cent,  on  10  pounds  of  wool  ?     So  that  one 
litre  would  be  equivalent  to  i  per  cent,  on  10  kilos  ? 


168  DYEING  AND    TEXTILE  CHEMISTRY. 

425.  Give  the  method  of  applying  substantive  colors  to  wool  in  a  slightly 
acid  bath.     What  acid  should  be  employed  and  why? 

426.  What  color  does  Chrysophenine  give  on  wool,  and  what  would  you 
say  as  to  its  fastness  to  light  ? 

427.  What  is  meant  by  "union"  material?    What  result  is  obtained  when 
this  is  dyed  with  Chrysophenine?     What  kind  of  dye-bath  is  employed? 

428.  If  union  material  is  dyed  in  an  acid  bath  with  Chrysophenine  and  Acid 
Violet  what  will  be  the  result? 

429.  What  is  the  purpose  of  after-treating  substantive  dyes  on  wool  with 
chrome?     How  is  the  process  conducted? 

430.  How  does  the  treatment  with  chrome  affect  the  tone  of  Diamine  Fast 
Red  ?     Compare  the  tests  to  washing  of  the  treated  and  untreated  samples. 

431.  How  is  the  after-treatment  with  chromium  fluoride  on  substantive 
colors  conducted?    What  influence  does  it  have  on  the  color?     How  does  it 
differ  in  its  action  from  chrome  ? 

432 .  Compare  the  results  of  the  tests  to  washing  of  the  samples  of  Columbia 
Green  treated  with  chromium  fluoride  and  untreated. 

433.  Give  an  example  of  a  substantive  dye  which  does  not  color  wool. 
What  conditions  are  most  favorable  for  a  minimum  amount  of  color  on  the 
wool  ?     In  what  connection  would  such  dyes  be  useful  ? 

434.  May  the  substantive  dyes  be  satisfactorily  applied  to  silk,  and  are  the 
colors  fast  ? 

435.  How  are  the  substantive  dyes  applied  to  silk  ?     Give  two  methods. 

436.  How  may  faster  shades  on  silk  with  the  substantive  colors  be  obtained  ? 
What  is  meant  by  half-silk,  and  why  are  the  substantive  colors  especially 
useful  on  such  material  ? 

437.  On  what  character  of  wool  material  are  the  substantive  dyes  mostly 
used  ?    Why  are  they  so  adaptable  for  dyeing  in  machines  ? 

438.  What  is  the  chief  recommendation  of  the  substantive  dyes  on  wool? 
Of  what  character  of  dyeings  is  this  especially  true?    Are  the  substantive 
colors  fast  to  stoving  ? 

439.  Does  the  fastness  of  the  substantive  colors  differ  when  dyed  on  wool 
from  that  on  cotton  ?     How  does  the  exhaustion  of  the  dye-bath  compare  with 
the  two  fibres? 

440.  In  general,  how  is  the  after-treatment  of  the  substantive  colors  on 
wool  with  chromium  salts  conducted?    How  much  chrome  or   chromium 
fluoride  should  be  used  ? 

441.  How  may  the  dyeings  be  after-treated  with  bluestone,  and  how  much 
of  this  salt  is  taken?    What  is  the  principal  effect  of  the  bluestone  on  the 
fastness  of  the  color? 

442.  What  is  the  method  of  obtaining  a  better  exhaustion  of  the  dye-bath 
for  after-treatment?    In  case  the  bath  does  not  exhaust  well,  how  should  the 
after-treatment  be  conducted? 


SUBSTANTIVE  DYES  ON   WOOL  AND   SILK.  169 

443.  What  is  the  most  serviceable  character  of  bath  in  dyeing  wool  with 
substantive  colors  ?    Why  should  the  baths  not  be  too  strongly  acid  ? 

444.  In  case  substantive  dyes  should  show  a  tendency  to  uneven  dyeing  on 
wool,  what  precautions  should  be  taken  ? 

445.  If  vegetable  matter  is  present  in  the  wool  when  dyeing  with  substantive 
colors  what  character  of  bath  should  be  used  and  why  ? 

446.  Are  the  substantive  colors  of  importance  in  the  dyeing  of  silk  ?     Why 
are  they  serviceable  for  the  dyeing  of  fancy  silk  threads  ? 

447.  How  should  light  shades  on  silk  be  dyed  with  the  substantive  colors? 
Heavy  shades? 

448.  What  precautions  should  be  taken  in  dyeing  silk  with  substantive 
colors  in  order  to  obtain  level  shades  ? 

449.  How  may  silk  be  brightened  after  dyeing  with  substantive  colors? 
Could  Congo  Red  on  silk  be  brightened,  and  why  ? 


SECTION   XV. 
REPRESENTATIVE  SUBSTANTIVE  DYES  ON  COTTON. 

Experiment  98.  Representative  Substantive  Dyes.  —  Dye 
skeins  of  cotton  yarn  in  baths  containing  i  per  cent,  of  soda  ash, 
20  per  cent,  of  common-salt,  and  2  per  cent,  of  the  respective 
dyes  named  below;  enter  at  160°  F.,  bring  to  the  boil,  and  dye  at 
that  temperature  for  one-half  hour,  then  wash  and  dry.  Use 
the  following  dyestuffs: 

(1)  Thioflavine  S  (Cass.)  (298). 

(2)  Diamine  Brown  30  (Cass.)  (299). 

(3)  Diamine  Bordeaux  B  (Cass.)  (300). 

(4)  Diamine  Orange  D  (Cass.)  (301). 

(5)  Chicago  Blue  6B  (Ber.)  (302). 

(6)  Columbia  Black  FB  (Ber.)   (303). 

(7)  Diamine  Rose  BD  (Cass.)  (304). 

(8)  Benzo  Fast  Scarlet  (Elb.)  (305). 

(9)  DianilBlue  G  (Metz)  (306). 
(10)  Dianil  Green  G  (Metz)  (307). 

Test  these  dyeings  for  fastness  to  washing  (308-317)  and 
water  (318-327). 

Make  a  record  of  your  results  as  follows: 


Dyestuff. 

Washing. 

Water. 

White 
wool. 

White 
cotton. 

Water. 

White 
cotton. 

Water. 



170 


REPRESENTATIVE  SUBSTANTIVE  DYES  ON  COTTON.      I /I 

NOTES. 

i.  Apparatus  for  Dyeing  Cotton  Yarn.  —  Wooden  vats  are 
generally  used  for  dyeing  cotton  in  the  form  of  hanks,  and  they 
are  usually  constructed  to  hold  50  or  100  pounds.  It  is  seldom 
they  are  made  larger  or  smaller  than  this  for  practical  work. 
During  the  dyeing  process  the  hanks  are  hung  on  smooth  rods, 
so  that  only  about  one-fourth  of  their  length  is  above  the  dye 
liquor.  The  yarn  is  turned  by  hand,  or  a  stick  may  be  used,  in 
which  case  a  pointed  stick  which  is  thinner  than  that  on  which 
the  yarn  hangs,  is  passed  through  the  hank  below  the  other  stick, 
and  the  yarn  is  then  raised  with  it  and  turned.  The  vats  must 
be  so  constructed  that  the  yarn  can  be  easily  turned  without  too 
much  water  being  required  in  proportion  to  the  cotton.  The 
following  are  suitable  internal  dimensions: 


For  50  pounds  yarn 


For  100  pounds  yarn 


length,  64  inches, 
breadth,  22 \  inches, 
depth,  23!  inches. 

length,  118  inches, 
breadth,  22 \  inches, 
depth,  23!  inches. 


The  dye  liquor  is  heated  by  a  steam-coil  which  may  enter  the 
liquor  at  the  top  end  of  the  vat.  If  the  vats  are  long,  two  coils 
may  be  used,  one  from  each  end,  but  if  short,  one  coil  will  be 
sufficient.  These  coils  are  closed  at  the  ends,  but  the  sides  are 
suitably  perforated  with  small  holes,  and  it  is  best  to  fix  them  on 
to  the  steam  pipe  with  a  union  joint  so  they  may  be  removed  from 
the  vat  if  necessary.  The  steam-coil  should  lie  under  a  perforated 
false  bottom  of  wood,  so  as  to  prevent  the  yarn  from  coming  in 
direct  contact  with  the  hot  pipe,  and  also  so  that  the  force  of  the 
escaping  steam  may  be  broken  and  disseminated  and  not  tangle 
up  the  yarn.  In  some  cases,  the  pipe  is  fitted  behind  a  perforated 
wooden  partition  which  stands  4  to  6  inches  from  the  top  end  of 
the  vat,  and  which  is  a  little  lower  than  the  latter.  This  arrange- 
ment offers  certain  advantages,  as  solutions  of  dyestuffs,  etc., 


172  DYEING   AND    TEXTILE   CHEMISTRY.  , 

may  be  poured  into  the  space  behind  it  during  the  dyeing  process 
and  gradually  distributed  through  the  liquor  without  having  to 
remove  the  yarn.  To  let  the  liquor  run  off  after  dyeing,  it  is  best 
to  have  the  vat  fitted  with  a  valve  which  can  be  opened  by  turning 
a  handle  from  the  outside.  The  old  method  of  having  a  plug  to 
be  drawn  is  bad,  as  the  workmen  are  liable  to  be  scalded.  The 
rods  on  which  the  yarn  is  hung  should  be  hard  straight  sticks  of 
hazel,  ash,  etc.,  from  which  all  knots  are  removed  so  that  no  rough 
places  are  left.  Besides  the  vat  method  of  dyeing,  cotton  yarn  may 
be  dyed  by  machines;  in  one  form  a  vat  is  used  as  with  hand 
dyeing,  but  the  sticks  are  turned  mechanically  by  a  system  of 
interacting  cogs.  In  another  form,  such  as  the  Klauder-Weldon 
machine,  the  rods  are  arranged  on  a  circular  spider  frame  rotating 
in  a  semicircular  vat,  the  sticks  also  being  turned  mechanically 
as  the  frame  rotates;  in  this  method,  only  one-half  the  load  of  yarn 
is  in  the  liquor  at  any  one  time,  so  that  economy  in  the  amount  of 
dye  liquor  is  effected;  the  yarn  is  also  kept  out  straight  by  being 
more  or  less  stretched  between  the  rods,  which  prevents  tangling. 
Another  method  of  machine  dyeing,  which  has  come  into  practice 
of  late,  and  which  may  also  be  employed  for  yarns,  though  it  is 
mostly  used  for  cops,  bobbins,  etc.,  is  where  the  material  is 
tightly  packed  in  a  chamber  of  metal  fixed  to  a  suction  tube  and 
pump;  the  cotton  remains  stationary  and  the  dyeing  is  effected  by 
forcing  the  heated  liquor  through  the  material.  Cotton  yarn  is 
also  largely  dyed  in  the  form  of  prepared  warps,  in  which  case 
a  special  warp-dyeing  machine  is  used,  the  warp  or  chain  run- 
ning over  rollers  up  and  down  through  the  vat  several  times, 
then  through  squeeze  rollers;  if  necessary  several  runs  are  made 
through  the  machine  to  obtain  the  desired  shade.  In  the  latter 
case,  the  machine  may  consist  of  several  compartments  each 
provided  with  squeeze  rollers,  and  the  yarn  is  run  through  each 
compartment  successively. 

2.  Apparatus  for  Dyeing  Woolen  Yarn.  —  This  material  is 
usually  dyed  in  wooden  vats  similar  to  those  just  described  for 
the  dyeing  of  cotton  yarn.  It  must  be  borne  in  mind,  however, 
that  for  woolen  yarn  dyed  on  sticks  in  large  vats  there  will  be 


REPRESENTATIVE  SUBSTANTIVE  DYES  ON  COTTON. 

required  about  300  to  450  gallons  of  water  for  100  pounds  of 
yarn,  depending  on  the  nature  of  the  material.  In  general  the 
yarn  is  entered  into  the  hot  acid  dye  liquor  (in  the  case  of  acid 
dyes)  and  is  dyed  for  ij  to  2  hours  at  the  boil.  About  2  to  3^ 
pounds  of  yarn  are  placed  on  each  stick,  and  for  a  zoo-pound  lot 
four  men  are  generally  employed  in  turning  at  the  beginning,  but 
later  only  two  men  are  required.  The  yarn  must  not  be  turned 
more  often  than  is  necessary  to  obtain  even  colors,  otherwise  the 
fibres  will  become  felted.  From  time  to  time  the  position  of  the 
sticks  should  be  changed,  that  is,  those  in  the  middle  of  the  vat 
should  be  moved  to  the  ends,  and  so  on.  On  a  first  kettle  when 
dyeing  woolen  yarn  it  is  usual  to  add  a  rather  large  quantity  of 
glaubersalt,  often  as  much  as  50  pounds  on  a  loo-pound  vat,  this 
being  a  great  help  toward  the  production  of  level  dyeings.  On 
subsequent  dyeings  in  the  same  vat  only  5  pounds  of  glaubersalt 
need  be  added.  As  a  rule,  old  dye  liquors  cannot  be  used  for 
longer  than  a  week;  though  there  are  exceptional  cases  where 
they  may  be  used  continuously  for  several  months.  As  a  rule, 
the  shades  on  woolen  yarn  are  not  perfectly  level  at  the  beginning 
of  the  process;  but  the  color  should  distribute  itself  evenly  after 
being  boiled  for  some  time;  generally,  the  dyeings  should  be 
perfectly  level  a  quarter  of  an  hour  after  the  color  solution  has  been 
added  to  the  bath.  Woolen  yarn  may  also  be  dyed  in  suitable 
machines  similar  to  those  used  for  cotton  dyeing,  the  Klauder- 
Weldon  form  of  machine  being  used  extensively  in  this  country, 
England,  and  Germany.  This  is  especially  true  for  fine  worsted 
yarns,  or  in  fact  any  kind  of  yarn  which  is  easily  matted  or 
tangled ;  in  such  cases  it  is  almost  impossible  to  obtain  satisfactory 
results  by  dyeing  by  hand  in  open  vats  on  sticks,  as  the  motion  of 
the  yarn  and  the  boiling  of  the  bath,  especially  if  live  steam  is  used 
for  heating,  cause  a  great  felting  and  tangling  of  the  threads. 
Such  yarn  is  best  dyed  in  a  Klauder-Weldon  machine,  where  the 
hanks  may  be  stretched  out  and  preserved  in  a  straight  condition 
throughout  the  dyeing  operation,  and  no  felting  will  result. 
Yarn  which  is  liable  to  curl  up,  due  to  tight  twist,  should  be 
scalded  before  washing  or  dyeing;  this  may  be  done  by  twisting 


DYEING   AND    TEXTILE   CHEMISTRY. 

the  hanks  together  tightly  and  laying  them  in  boiling  water 
for  a  couple  of  hours,  then  allowing  them  to  cool  before  untwist- 
ing. In  using  the  Klauder-Weldon  machine  for  dyeing  or  scour- 
ing, this  previous  scalding  will  be  superfluous,  as  the  yarn  will 
naturally  undergo  this  operation  when  stretched  in  the  machine 
during  the  dyeing  process  itself.  With  such  yarn,  however,  the 
hanks  should  not  be  unstretched  until  they  have  passed  through 
cold  water  or  have  cooled  down. 

3.  Apparatus  for  Dyeing  Silk  Yarn.  —  Small  lots  of  silk  yarn 
are  usually  dyed  in  copper  boilers,  and  larger  lots  in  copper  or 
copper-plated   vats.     These   are   usually   mounted   on   wheeled 
frames,  so  that,  with  the  exception  of  the  long  heavy  vats,  they 
may  be  conveniently  moved  about  the  dyehouse.     This  arrange- 
ment is  a  desirable  one,  as  the  dyer  requires  to  use  larger  or  smaller 
vats  according  to  the  quantity  of  silk  which  has  to  be  dyed  at  one 
time.     As  the  vats  are  often  used  for  the  most  varying  shades,  it 
is  necessary  to  frequently  cleanse  them  thoroughly.     For  this 
purpose  they  may  be  first  boiled  out  with  old  boiled-off  liquor, 
or  the  inner  sides  may  be  thoroughly  scoured  with  a  hot  strong 
solution  of  soda  ash.    After  this  has  been  run  out,  the  vat  is  rinsed 
with  water  and  then  cleansed  again  with  dilute  sulphuric  acid, 
and  finally  rinsed  out  again  with  water.     The  larger  vats,  which 
are  stationary,  are  generally  heated  with  a  steam-coil  placed  under 
a  perforated  false  bottom;  for  the  smaller  vats,  usually  movable 
steam-pipes  are  inserted.     These  steam-pipes  should  be  fitted  so 
as  to  turn  in  a  ball-and-socket  joint  so  that  they  may  be  moved 
around  in  any  direction.     The  silk  is  hung  in  hanks  on  smooth 
rods  in  the  same  manner  as  wool  or  cotton,  about  one-half  pound 
of  silk  being  distributed  on  each  stick.     Silk  may  also  be  dyed  in 
machines,  the  chief  form   in  this  country  being  the  Klauder- 
Weldon,   for  which  purpose  a  special  machine   is  constructed. 
The  spider  is  so  arranged  that  at  any  time  the  entire  lot  of  yarn 
may  be  raised  out  of  the  liquor. 

4.  List  of  the  Principal  Substantive  Dyes  for  Cotton.  —  The 
substantive  dyes  form  a  very  large  and  ever-increasing  group. 
Although  the  most  of  them  are  applied  almost  exclusively  to 


REPRESENTATIVE  SUBSTANTIVE  DYES  ON  COTTON.    I?$ 


cotton,  nevertheless  many  of  them  are  also  used  for  dyeing  wool 
and  silk.  Some  of  the  substantive  dyes  are  also  adapted  for 
after-treatment  with  bluestone  and  chrome.  These  are  indicated 

in  a  separate  list. 

(a)  RED. 

Diamine  Red  B,  36,  46,  56,  6B,  loB, 


Acetopurpurine  8B 

Alkali  Bordeaux. 

Alkali  Grenat. 

Alkali  Purpurine. 

Alkali  Red,  and  76. 

Azo  Purpurine. 

Benzo  Bordeaux. 

Benzo  Fast  Red  L  and  GL. 

Benzo  Fast  Rose. 

Benzo  Fast  Scarlet. 

Benzopurpurine  B,  46,  6B,  and  zoB. 

Benzo  Red  loB  and  SG. 

Benzo  Rhoduline  Red  B  and  36. 

Brilliant  Congo. 

Brilliant  Geranine. 

Brilliant  Purpurine  46  and  loB. 

Chicago  Red. 

Chlorantine  Red  46  and  8B. 

Columbia  Red  46  and  8B. 

Congo  Red. 

Congo  Rubine. 

Cotton  Red  46. 

Deltapurpurine  56  and  76,  and  G. 

Diamine  Bordeaux  B  and  S. 

Diamine  Brilliant  Scarlet  S. 

Diamine  Fast  Red  F. 


NO,  and  D. 

Diamine  Rose  BD,  BG,  and  GD. 
Diamine  Scarlet  B,  36,  and  HS. 
Diamine  Violet  Red. 
Dianil  Ponceau  G  and  2R. 
Direct  Scarlet. 
Erika. 

Geranine  G  and  26. 
Hessian  Bordeaux. 
Hessian  Brilliant  Purple. 
Hessian  Fast  Rubine. 
Hessian  Purple  B,  D,  and  N. 
Oxamine  Bordeaux. 
Oxamine  Grenat. 
Oxamine  Maroon. 
Oxamine  Red. 
Purpuramine. 
Rosazurine  B  and  G. 
Rosophenine. 
Salmon  Red. 
St.  Denis  Red. 
Thiazine  Red. 
Toluylene  Red. 
Trona  Red. 


Alkali  Orange. 
Benzo  Fast  Orange  S. 
Benzo  Orange  R. 
Brilliant  Orange  G. 
Chicago  Orange. 
Chloramine  Orange. 
Columbia  Orange. 
Congo  Orange  G  and  R. 
Cotton  Orange  G  and  R. 
Diamine  Fast  Orange. 
Diamine  Orange. 


ORANGE. 

Dianil  Orange. 
Direct  Orange. 
Mikado  Orange. 
Naphthamine  Orange. 
New  Toluylene  Orange. 
Orange  TA. 
Oxydiamine  Orange. 
Pluto  Orange  G. 
Pyramine  Orange  R  and  3G. 
Toluylene  Orange. 


1 76  DYEING  AND    TEXTILE  CHEMISTRY. 

(c)  YELLOW. 

Alkali  Yellow  R.  Direct  Yellow  G  and  36,  L,  R,  T,  and 

Brilliant  Yellow.  TG. 

Carbazol  Yellow.  Hessian  Yellow. 

Chloramine  Yellow  GG  and  M.  Mekong  Yellow. 

Chlorantine  Yellow  T.  Mikado  Gold  Yellow. 

Chromine  G.  Mikado  Yellow. 

Chrysamine  G  and  R.  Mimosa. 

Chrysophenine.  Naphthamine  Yellow. 

Columbia  Yellow.  Oriol. 

Cotton  Yellow  G  and  R.  Oxydiamine  Yellow. 

Curcumine  S.  Oxydianil  Yellow. 

Diamine  Fast  Yellow.  Polyphenyl  Yellow. 

Diamine  Gold.  Salicine  Yellow  G  and  GG. 

Diamine  Yellow.  Sun  Yellow. 

Dianil  Yellow.  Thiazol  Yellow  G  and  R. 

Diphenyl  Chrysoin.  Thioflavine  S. 

Diphenyl  Citronine.  Xanthine. 

Diphenyl  Fast  Yellow.  Yellow  CR  and  D. 

(d)  GREEN. 

Alkali  Green.  Diamine  Dark  Green. 

Benzo  Dark  Green  B  and  GG.  Diamine  Green. 

Benzo  Green  BB  and  G.  Direct  Green. 

Benzo  Olive.  Eboli  Green. 

Brilliant  Benzo  Green.  Oxamine  Dark  Green. 

Chloramine  Green.  Oxamine  Green. 

Columbia  Dark  Green.  Tolamine  Green. 
Columbia  Green. 

(e)  BLUE. 

Acetylene  Blue.  Benzo  Indigo  Blue. 

Alkali  Azo  Blue.  Benzo  Marine  Blue. 

Azo  Blue.  Benzo  Pure  Blue. 

Azo  Corinth.  Benzo  Red  Blue  G. 

Azo  Dark  Blue.  Brilliant  Azurine. 

Azo  Mauve.  Brilliant  Benzo  Blue  6B. 

Benzo  Azurine  G,  3G,  and  R.  Chicago  Blue. 

Benzo  Blue.  Chlorazol  Blue. 
Benzo  Chrome  Dark  Blue  B  and  N*        Columbia  Blue. 

Benzo  Copper  Blue  B.  Columbia  Fast  Blue. 

Benzo  Cyanine  B,  36,  and  R.  Columbia  Dark  Blue. 

Benzo  Dark  Blue  R,  G,  and  56.  Congo  Blue. 

Benzo  Fast  Blue.  Congo  Fast  Blue. 


REPRESENTATIVE  SUBSTANTIVE  DYES  ON  COTTON.    1/7 

(e)  BLUE.  —  Continued. 

Congo  Pure  Blue.  Erie  Blue  BX  and  2G. 

Diamine  Azo  Blue  R  and  2R.  Naphthamine  Blue. 

Diamine  Blue  BX,  RW,  BG,  26,  36.      Naphthamine  Deep  Blue. 

Diamine  Brilliant  Blue  G.  Naphthamine  Indigo. 

Diamine  Dark  Blue.  Naphthazurine. 

Diamine  Fast  Blue.  Naphthyl  Blue  BB. 

Diamine  New  Blue.  New  Toluylene  Blue. 

Diamine  Pure  Blue.  Oxamine  Blue. 

Diamine  Sky  Blue.  Oxamine  Dark  Blue. 

Diamine  Steel  Blue.  Oxydiamine  Blue  R,  3R,  and  G. 

Diamineral  Blue.  Phenamine  Blue. 

Diphenyl  Blue  3&.  Toledo  Blue  V. 

Direct  Blue  B,  -2BX,  and  3BX.  Toluylene  Blue. 

Direct  Blue  B  and  R.  Toluylene  Dark  Blue. 

Direct  Indigo  Blue.  Triamine  Blue. 

Eboli  Blue  B,  6B,  and  2R.  Triazol  Blue. 

(/)  VIOLET. 

Alkali  Azo  Violet.  Congo  Violet. 

Azo  Corinth.  Diamine  Heliotrope  G,  O,  and  B. 

Azo  Gallein.  Diamine  Violet  N. 

Azo  Mauve.  Dianil  Bordeaux. 

Azo  Violet.  Direct  Violet. 

Benzo  Fast  Violet.  Heliotrope. 

Benzo  Violet.  Hessian  Bordeaux. 

Bordeaux  Extra.  Hessian  Violet. 

Bordeaux  COV.  Oxamine  Violet. 

Chloramine  Violet.  Oxydiamine  Violet  B,  R,  and  G. 

Chlorantine  Lilac.  Triazol  Violet. 

Clemantine.  Trisulphon  Violet. 

Congo  Corinth. 

(g)  BROWN. 

Alkali  Brown.  Chlorantine  Brown. 

Alkali  Dark  Brown.  Columbia  Brown. 

Alkali  Red  Brown.  Congo  Brown. 

Benzo  Brown.  Cotton  Brown. 

Benzo  Chrome  Brown.  Diamine  Bronze. 

Catechu  Brown.  Diamine  Brown. 

Chicago  Brown.  Diamine  Catechine. 


178  DYEING  AND   TEXTILE  CHEMISTRY. 

(g)  BROWN.  —  Continued. 

Diamine  Fast  Brown.  Naphthamine  Brown. 

Diamine  Nitrazol  Brown.  New  Toluylene  Brown. 

Diamineral  Brown.  Oxamine  Brown. 

Diazo  Brown.  Oxamine  Maroon. 

Diphenyl  Brown.  Oxydiamine  Brown. 

Direct  Brown.  Pluto  Brown. 

Direct  Bronze  Brown.  Terra  Cotta. 

Direct  Fast  Brown.  Thiazine  Brown. 

Fast  Cotton  Brown.  Toluylene  Brown. 

Hessian  Brown.  Trisulphon  Brown. 

Mikado  Brown.  Zambesi  Brown. 


(H)  BLACK. 

Alkali  Black  B  and  G.  Diphenyl  Blue  Black. 

Benzo  Chrome  Black.  Diphenyl  Black. 

Benzo  Chrome  Blue  Black.  Diphenyl  Fast  Black. 

Benzo  Fast  Black.  Direct  Black. 

Carbide  Black.  Direct  Blue  Black. 

Chromanil  Black.  Direct  Deep  Black. 

Cold  Black.  Isodiphenyl  Black. 

Columbia  Black.  Melantherine. 

Cotton  Black.  Naphthamine  Black. 

Diamine  Black.  Nyanza  Black. 

Diamine  Blue  Black.  Oxamine  Black. 

Diamine  Deep  Black.  Oxydiamine  Black. 

Diamine  Jet  Black.  Pluto  Black. 

Diamineral  Black.  Polyphenyl  Black. 

Diaminogene  B,  and  extra.  Tabora  Black. 

Dianil  Black.  Toluylene  Black. 

Diazo  Black.  Violet  Black. 

Diazo  Blue  Black.  Zambesi  Black. 


(i)  GRAY. 

Benzo  Fast  Gray.  Fast  Gray. 

Chicago  Gray.  Hessian  Copper  Gray. 

Diamine  Gray.  Hessian  Gray. 

Diphenyl  Gray.  Neutral  Gray. 

Direct  Gray.  Zambesi  Gray. 


REPRESENTATIVE  SUBSTANTIVE  DYES  ON  COTTON.      1 79 


5.   Substantive  Dyes  Suitable  for  After-treatment  with  Blue- 
stone. 


Azo  Violet. 

Benzo  Azurine  G,  3G,  and  R. 

Benzo  Blue. 

Benzo  Copper  Blue  B. 

Benzo  Cyanine  B,  36,  and  R. 

Benzo  Pure  Blue. 

Brilliant  Azurine. 


Brilliant  Benzo  Blue  6B. 
Chloramine  Violet  R. 
Chrysamine  G  and  R. 
Diamine  Blue  RW. 
Diamine  Pure  Blue. 
Hessian  Copper  Gray. 
Pluto  Orange  G. 


6.   Substantive  Dyes  Suitable  for  After-treatment  with  Chrome 
and  Bluestone. 


Benzo  Chrome  Black  B  and  N. 
Benzo  Chrome  Blue  Black  B. 
Benzo  Chrome  Brown. 
Carbide  Black  BO. 
Catechu  Brown. 
Chromanil  Black. 
Chromanil  Brown. 
Chrysamine  G  and  R. 


Columbia  Chrome  Black. 
Cupranil  Brown. 
Diamine  Catechine. 
Diamineral  Black. 
Direct  Deep  Black  E  extra. 
Direct  Deep  Black  RW  extra. 
Pluto  Orange  G. 
Trisulphon  Brown  S. 


7.   Principal  Substantive  Dyes  Applicable  to  Wool. 

(a)  RED. 


Anthracene  Red. 

Benzo  Bordeaux  6B. 

Benzo  Fast  Red  L. 

Benzo  Purpurine  B,  46,  6B,  and  loB. 

Benzo  Red  loB. 

Benzo  Rhoduline  Red. 

Brilliant  Congo  R. 

Brilliant  Geranine  B. 

Brilliant  Purpurine  R. 

Congo  Red. 

Congo  Rubine. 


Delta  Purpurine  56  and  76. 

Diamine  Bordeaux  B  and  S. 

Diamine  Fast  Red  F. 

Diamine  Red  NO,  D,  56,  and  loB. 

Diamine  Scarlet  B,  36,  and  HS. 

Geranine  G  and  BB. 

Hessian  Bordeaux. 

Hessian  Brilliant  Purple. 

Hessian  Purple. 

Rosazurine  B,  G. 


Alkali  Orange. 
Benzo  Fast  Orange  S. 
Brilliant  Orange  G. 
Congo  Orange  G  and  R. 
Cotton  Orange  G  and  R. 


(b)  ORANGE. 

Direct  Orange  R  and  2R. 
Mikado  Orange. 
Orange  TA. 
Pluto  Orange  G. 
Toluylene  Orange  G  and  R. 


Diamine  Orange  B,  G,  D,  GC,  and  DC. 


i8o 


DYEING  AND    TEXTILE   CHEMISTRY. 


Brilliant  Yellow. 
Carbazol  Yellow. 
Chloramine  Yellow  M. 
Chrysamine  G  and  R. 
Chrysophenine. 
Cotton  Yellow  R. 
Curcumine  S  and  W. 
Diamine  Fast  Yellow  A. 
Diamine  Gold  Yellow. 
Diamine  Yellow  N. 


Benzo  Dark  Green  B,  2G. 
Benzo  Green  2B  and  G. 


(c)  YELLOW. 

Diphenyl  Citronine. 
Diphenyl  Fast  Yellow. 
Hessian  Yellow. 
Mikado  Yellow. 
Polyphenyl  Yellow. 
Salicine  Yellow  G,  2G. 
Sun  Yellow  3G. 
Thiazol  Yellow  G  and  R. 
Thioflavine  S. 


(d)  GREEN. 

Diamine  Green  B. 
Eboli  Green  S  and  ST. 


(e)  BLUE. 


Azo  Blue. 

Benzo  Azurine  G,  3G,  and  R. 

Benzo  Blue  26,  36,  and  BX,  2R,  4R, 

and  RW. 

Benzo  Cyanine  B  and  R. 
Chicago  Blue  B. 
Congo  Blue  26. 
Diamine  Blue  26,  36,  and  BX,  3R, 

and  RW. 
Diamine  Brilliant  Blue. 


Diamine  New  Blue  G  and  R. 
Diamine  Pure  Blue  FF. 
Eboli  Blue. 
Toledo  Blue. 

Most  of  the  blue  substantive  dyes 
exhaust  but  poorly  on  wool  from  a 
neutral  bath;  better  results  are 
obtained  by  the  addition  of  a  small 
amount  of  acetic  acid,  or  under  some 
conditions,  of  sulphuric  acid. 


Azo  Violet. 
Chloramine  Violet. 
Congo  Corinth  B  and  G. 


(/)  VIOLET. 

Diamine  Violet  N. 
Diazo  Black  H  and  R. 
Hessian  Violet. 


Benzo  Brown. 

Benzo  Chrome  Brown  G,  5G,  R,  and 

3*- 

Cotton  Brown  A  and  N. 

Diamine  Bronze  G. 

Diamine  Brown  B,  3G,  M,  and  V. 


(g)  BROWN. 

Diazo  Brown  G. 

Direct  Fast  Brown  B  and  2G. 

Pegu  Brown. 

Pluto  Brown  2G,  NB,  and  R. 

Toluylene  Brown. 


REPRESENTATIVE  SUBSTANTIVE  DYES  ON  COTTON.    l8l 

(K)  BLACK. 

Benzo  Fast  Black.  Diazo  Black  36,  BHN. 

Diamine  Black  BH,  HW.  Direct  Deep  Black  E  extra,  and  RW. 

Diamine  Deep  Black  28,  2O.  Oxydiamine  Black  N,  SOOO. 

(i)  The  following  colors  may  also  be  applied  to  wool  if  a  considerable 
amount  of  acetic  acid  be  added  to  the  dye-bath. 

Benzo  Fast  Scarlet  468  and  GS.  Brilliant  Benzo  Blue  6B. 

Benzo  Fast  Violet  R.  Chloramine  Orange  G. 

Benzo  Orange  R.  Direct  Blue  Black  B,  26,  and  N. 

Benzo  Pure  Blue  46.  Direct  Deep  Black  G. 

Benzo  Violet  R.  Heliotrope  26. 

Brilliant  Azurine  B,  G,  and  5G.  Pluto  Black  G  and  F. 

SAMPLES. 

298.  Thioflavine  S  on  cotton. 

299.  Diamine  Brown  3G  on  cotton. 

300.  Diamine  Bordeaux  B  on  cotton. 

301.  Diamine  Orange  D  on  cotton. 

302.  Chicago  Blue  6B  on  cotton. 

303.  Columbia  Black  FB  on  cotton. 

304.  Diamine  Rose  BD  on  cotton. 

305.  Benzo  Fast  Scarlet  on  cotton. 

306.  Dianil  Blue  G  on  cotton. 

307.  Dianil  Green  G  on  cotton. 
308-317.   Tests  for  fastness  to  washing. 
318-327.  Tests  for  fastness  to  water. 

QUIZ  15. 

450.  What  color  does  Thioflavine  S  give  on  cotton  ?    Name  five  substantive 
dyestuffs  and  the  firms  which  manufacture  them. 

451.  Of  the  ten  substantive  dyestuffs  tested,  which  ones  were  found  to  be 
the  fastest  to  washing  ?     How  was  the  washing  test  made  ? 

452.  Which  of  the  substantive  dyes  were  found  to  be  fastest  to  water? 
How  was  the  water  test  made  ? 

453.  Describe  the  necessary  apparatus  required  for  dyeing  100  pounds  of 
cotton  by  hand.     What  is  the  usual  breadth  and  depth  of  dye-vats? 

454.  What  is  the  usual  length  of  a  vat  for  dyeing  50  pounds  of  cotton  yarn  ? 
For  dyeing  100  pounds? 

455.  How  may  the  dye  liquor  be  heated  in  the  vat?    Why  should  a  perfo- 
rated false  bottom  be  used?    What  advantage  is  there  in  having  the  coil  in 
an  end  partition? 


1 82  DYEING   AND    TEXTILE   CHEMISTRY. 

456.  What  character  of  rods  should  be  used  for  hanging  the  hanks  of  yarn 
on? 

457.  In  what  forms  of  machines  may  cotton  yarn  be  dyed?     Describe  the 
Klauder-Weldon  machine.     What  advantages  does  this  offer? 

458.  Describe  the  general  principle  of  the  pressure  or  suction  dyeing 
machines.     What  advantages  and  disadvantages  do  machines  of  this  type 
possess? 

459.  How  are  cotton  warps  dyed?    What  are  the  advantages  of  warp 
dyeing? 

460.  Assuming  a  breadth  of  22  inches  and  a  depth  of  24  inches,  a  vat  of 
what  length  would  be  required  for  the  dyeing  of  100  pounds  of  woolen  yarn, 
supposing  600  gallons  U.  S.  to  be  used  in  the  dye-vat? 

461.  How  much  woolen  yarn  may  be  placed  on  each  stick  in  the  dye-vat, 
and  how  many  men  are  required  for  turning?     Supposing  that  4  men  at  $1.25 
per  day  of  10  hours  can  run  two  vats  of  100  pounds  each,  and  that  the  time 
of  dyeing,  washing,  etc.,  for  each  lot  is  2\  hours,  what  would  be  the  wage  cost 
of  dyeing  2000  pounds  of  woolen  yarn  ? 

462.  In  using  standing  kettles  in  dyeing  loo-pound  lots,  with  how  much 
glaubersalt  is  the  first  bath  charged  generally  in  practice  ?    How  much  is  added 
to  subsequent  baths  ? 

463.  For  what  length  of  time,  as  a  rule,  may  standing  kettles  be  run  when 
dyeing  woolen  yarn  in  acid  baths  ? 

464.  Does  the  color  on  woolen  yarn,  as  a  rule,  come  up  level  on  first  starting 
the  dyeing?    What  reason  do  you  assign  to  this?    What  causes  the  color  to 
distribute  itself  evenly  and  in  what  time  should  it  level  up  ? 

465.  What  character  of  machines  may  be  used  for  dyeing  woolen  yarn? 
For  what  kind  of  yarn  is  the  Klauder-Weldon  machine  especially  adapted  ? 

466.  Woolen  yarn  which  is  liable  to  curl  up  should  be  treated  in  what 
manner  before  dyeing  ?     Give  an  explanation  of  this  process. 

467.  Is  a  previous  scalding  of  curly  yarn  necessary  when  using  a  Klauder- 
Weldon  machine  for  dyeing?    Why? 

468.  What  kind  of  vats  are  used  for  the  dyeing  of  silk  yarns  ?     Explain  the 
manner  of  cleaning  the  vats  when  using  different  colors. 

469.  How  much  silk  should  be  placed  to  a  stick  in  dyeing  by  hand?    In 
what  character  of  machines  may  silk  yarn  be  dyed  ? 

470.  Describe  the  Klauder-Weldon  machine  employed  especially  for  the 
dyeing  of  silk. 


SECTION   XVI. 
APPLICATION  OF  MORDANT  DYES  TO  WOOL. 

Experiment  99.  General  Method  of  Dyeing.  —  The  most 
generally  used  mordant  for  wool  is  chrome  or  potassium  bichro- 
mate. It  is  applied  to  the  fibre  in  the  following  manner :  Prepare 
a  bath  containing  3  per  cent,  of  chrome  and  4  per  cent,  of  tartar; 
enter  a  test-skein  of  woolen  yarn  at  140°  F.,  gradually  raise  to 
the  boil,  and  continue  at  that  temperature  for  one-half  hour; 
wash  well,  and  then  dye  in  a  fresh  bath  containing  2  per  cent. 
Alizarin  Blue  NG  and  4  per  cent,  of  calcium  acetate;  enter  at 
100°  F.,  gradually  raise  to  the  boil,  and  dye  at  that  temperature 
for  one-half  hour;  then  add  2  per  cent,  of  acetic  acid  and  boil  for 
15  minutes  longer;  wash  well  and  dry  (328).  Chrome,  or  potas- 
sium bichromate,  is  a  salt  of  chromic  acid  (CrO3),  while  the 
mordant  which  is  eventually  produced  on  the  fibre  is  chromium 
oxide  (Cr2O3);  hence  in  the  process  of  mordanting  the  chrome 
must  undergo  reduction.  This  is  brought  about  partly  by  the 
wool  itself,  but  chiefly  by  the  aid  of  the  tartar.  The  latter  is 
potassium  acid  tartrate,  or  potassium  bitartrate,  and  is  a  reducing 
agent.  After  mordanting  it  will  be  noticed  that  the  wool  is 
yellow  in  color;  this  is  probably  due  to  the  formation  of  chromium 
chromate  in  the  fibre.  If  this  compound  is  exposed  to  the  action 
of  strong  light  it  will  suffer  a  rapid  reduction  to  chromium  oxide, 
which  is  green  in  color;  hence  it  is  best  not  to  expose  the  mor- 
danted wool  unevenly  to  light  for  any  length  of  time  before 
dyeing. 

Experiment  100.  Effect  of  Iron  Salts  in  the  Bath.  —  Alizarin 
colors  are  much  affected  by  the  presence  of  iron  salts  in  either 
the  mordant  or  the  dye-bath,  the  color  being  considerably  dulled 
through  the  formation  of  an  iron  color-lake  with  the  dyestuff. 

183 


1 84  DYEING  AND    TEXTILE  CHEMISTRY. 

To  show  this  influence  in  the  mordant  bath,  mordant  a  skein  of 
woolen  yarn  in  a  bath  containing  3  per  cent,  of  chrome,  4  per  cent, 
of  tartar,  and  a  few  drops  of  a  solution  of  copperas.  After  mor- 
danting (329),  dye  as  usual  with  2  per  cent,  of  Alizarin  Blue  NG; 
wash  and  dry  (330),  and  compare  the  color  thus  obtained  with 
that  produced  with  the  same  mordant  and  dyestuff  without  the 
addition  of  the  iron  salt.  Mordant  a  second  skein  of  woolen 
yarn  in  the  usual  manner  with  3  per  cent,  of  chrome  and  4  per 
cent,  of  tartar,  and  dye  as  before  with  2  per  cent,  of  Alizarin 
Blue  NG,  but  add  to  the  dye-bath  a  few  drops  of  a  solution  of 
copperas.  Notice  the  effect  of  this  on  the  appearance  of  the 
color  (331). 

Experiment  101.  Comparison  of  Different  Mordants  on  Wool. — 
Mordant  a  skein  of  woolen  yarn  in  a  bath  containing  3  per  cent, 
of  chrome  and  4  per  cent,  of  tartar;  enter  at  i4o°F.,  gradually 
bring  to  the  boil,  and  continue  at  that  temperature  for  one-half 
hour;  wash  well  (332)  and  dye  in  a  fresh  bath  containing  2  per 
cent,  of  Alizarin  Red  SW;  enter  at  100°  F.,  gradually  bring  to  the 
boil,  and  dye  at  that  temperature  for  one-half  hour,  then  wash 
well  and  dry  (333). 

Mordant  a  second  skein  of  woolen  yarn  in  the  same  manner  in 
a  similar  bath,  but  instead  of  using  chrome  use  10  per  cent,  of 
alum;  wash  well  (334),  and  dye  as  before  with  2  per  cent,  of 
Alizarin  Red  SW  (335). 

Mordant  a  third  skein,  using  8  per  cent,  of  copperas  as  the 
mordant  with  6  per  cent,  of  tartar;  wash  well  (336),  and  dye  with 
2  per  cent,  of  Alizarin  Red  SW  (337). 

Mordant  a  fourth  skein  with  5  per  cent,  of  bluestone  (338)  and 
4  per  cent,  of  tartar;  wash  well,  and  dye  with  2  per  cent,  of  Alizarin 
Red  SW  (339). 

Mordant  a  fifth  skein  with  4  per  cent,  of  stannous  chloride  and 
2  per  cent,  of  oxalic  acid ;  wash  well  (340) ,  and  dye  with  2  per  cent, 
of  Alizarin  Red  SW  (341). 

Compare  the  several  colors  obtained  on  the  different  mordants 
with  the  same  dyestuff,  and  also  preserve  samples  of  the  original 
mordanted  yarn  before  dyeing  in  each  case,  so  as  to  be  able  to 


APPLICATION  OF  MORDANT  DYES   TO   WOOL. 


I85 


compare  the  colors  given  by  the  mordants  alone.     Make  a  record 
of  your  results  as  follows: 


Mordant. 

Color  of  mordanted  skein. 

Color  of  dyed  skein. 

Chromium.  

Aluminium 

Iron 

Copper                 

Tin     

Experiment  102.  After-Mordanting  with  Chrome.  —  This 
method  may  be  used  with  quite  a  number  of  the  alizarin  colors, 
and  is  becoming  a  favorite  process,  as  only  one  bath  is  required. 
Dye  a  skein  of  woolen  yarn  in  a  bath  containing  2  per  cent,  of 
Anthracene  Yellow  C,  2  per  cent,  of  sulphuric  acid,  and  20  per  cent, 
of  glaubersalt;  enter  at  120°  F.,  gradually  bring  to  the  boil,  and 
continue  at  that  temperature  for  one-half  hour;  then  lift  the  skein 
(342a)  and  add  3  per  cent,  of  chrome,  and  continue  the  boiling 
for  15  minutes;  wash  and  dry  (342!)).  Preserve  a  sample  of  the 
color  before  chroming  and  compare  it  with  the  chromed  color. 
Many  of  the  alizarins  are  now  prepared  in  such  a  manner  that 
they  have  slight  acid  properties  and  are  capable  of  being  absorbed 
by  the  wool  fibre  from  acid  baths;  these  alizarins  are  chiefly  in 
the  powder  form,  and  are  compounds  of  the  dyestuffs  with  sodium 
bisulphite;  they  are  also  much  more  soluble  in  water  than  the 
ordinary  alizarins. 

Dye  a  skein  of  woolen  yarn  in  a  bath  containing  4  per  cent,  of 
acetic  acid,  2  per  cent,  of  Acid  Alizarin  Green  R,  and  20  per  cent,  of 
glaubersalt  (343*).  Dye  in  the  same  manner  as  before  and  then 
add  3  per  cent,  of  chrome  as  above;  wash  well  and  dry  (343b). 

Dye  a  third  skein  in  a  bath  containing  2  per  cent,  of  sulphuric 
acid,  4  per  cent,  of  Diamond  Black  GA,  and  20  per  cent,  of  glau- 
bersalt (344) ;  dye  as  before  and  after-chrome  with  2  per  cent,  of 
chrome  and  i  per  cent,  of  sulphuric  acid;  wash  well  and  dry  (345). 


1 86 


DYEING   AND    TEXTILE   CHEMISTRY, 


Dye  a  fourth  skein  with  2  per  cent,  of  Diamond  Flavine  (346)  in 
the  same  manner  and  after-chrome;  wash  and  dry  (347).  In  each 
case  preserve  a  sample  of  the  skein  before  chroming  in  order  to 
observe  any  change  in  the  color  due  to  the  chroming. 

Test  these  colors  as  to  their  fastness  to  washing  and  acids. 

Make  a  record  of  your  results  in  the  following  manner: 


Effect  of 

T 

Vashing  test 

Acid 

chroming. 

Color. 

White 
wool. 

White 
cotton. 

test. 

Anthracene  Yellow  C 

Acid  Alizarin  Green  R  . 

Diamond  Black  GA  

Diamond  Flavine 

NOTES. 

i .  The  Mordanting  of  Wool.  —  In  mordanting  wool  with 
chrome  the  mordanting  bath  is  not  exhausted  and  may  be  used 
again  for  fresh  lots  of  wool,  adding  about  2  per  cent,  of  chrome 
and  3  per  cent,  of  tartar  each  time.  After  mordanting  the  wool 
should  be  well  washed  in  order  to  remove  the  excess  of  mordanting 
liquor  from  the  fibre,  which  coming  in  contact  with  the  dye  liquor 
would  cause  a  loss  of  coloring-matter  by  precipitation  and  also 
form  a  loosely  adherent  surface  color-lake  on  the  fibre  which 
would  eventually  rub  off  badly  and  cause  the  color  to  smut  or 
crock.  It  has  been  demonstrated  that  about  3  per  cent,  of  chrome 
is  the  proper  amount  of  mordant  to  employ  for  full  shades  of 
alizarin  colors;  for  lighter  shades  less  mordant  may  be  used.  If 
larger  quantities  than  3  per  cent,  are  employed,  the  color  is  liable 
to  be  injured  and  will  not  be  as  heavy  or  as  bright  as  when  only 
3  per  cent,  is  used.  The  use  of  too  much  chrome  also  has  the 
effect  of  oxidizing  the  wool  fibre  itself,  causing  it  to  become 
harsh,  and  with  some  dyes  to  take  up  less  coloring-matter.  In 
place  of  using  tartar  as  the  assistant  in  the  mordanting  process, 


APPLICATION  OF  MORDANT  DYES   TO   WOOL.  l8/ 

there  may  be  employed  such  substances  as  oxalic  acid,  lactic 
acid,  formic  acid,  lactoline  (which  is  potassium  bilactate),  lig- 
norosin  (which  is  a  substance  obtained  from  the  spent  liquors  in 
the  bisulphite  method  of  bleaching  wood  pulp);  sulphuric  or 
hydrochloric  acids  may  ,  also  be  used,  and  sodium  bisulphate 
(which  is  sold  as  "tartar  substitute")  is  frequently  employed 
where  cheapness  is  more  desirable  than  quality.  It  is  the  general 
opinion,  however,  that  tartar  furnishes  the  best  all-round  results. 
Lactic  acid  employed  in  connection  with  sulphuric  acid  is  a  very 
good  assistant  where  heavy  shades,  such  as  blues,  browns,  etc., 
are  to  be  dyed;  it  causes  a  complete  reduction  and  exhaustion  of 
the  mordanting  bath  and  only  requires  the  use  of  about  2  per  cent, 
of  chrome  in  place  of  the  usual  3  per  cent. ;  it  causes  the  mordanted 
wool  to  have  a  very  decided  greenish  color,  however,  and  on  this 
account  does  not  give  as  good  results  as  tartar  in  certain  shades. 
The  use  of  formic  acid  as  a  chrome  assistant  is  becoming  of  some 
importance. 

2.  Dyeing  Wool  with  Mordant  Colors.  —  Calcium  acetate  is 
added  to  the  dye-bath  for  the  purpose  of  brightening  the  color, 
and  it  is  supposed  that  a  triple  color-lake  is  formed  between  the 
chromium,  the  calcium,  and  the  alizarin.  Where  the  water 
employed  for  the  dye-bath  is  sufficiently  hard  (that  is,  contains 
sufficient  lime  salts  in  solution)  the  addition  of  acetic  acid  in 
requisite  amounts  will  form  the  necessary  calcium  acetate,  hence 
none  of  this  salt  need  be  added  under  such  conditions.  For 
water  of  5  degrees  to  10  degrees  of  hardness  (one  degree  of 
hardness  represents  i  part  of  lime  in  100,000  parts  of  water) 
2  parts  of  acetic  acid  (of  9°  Be.)  should  be  added  for  each  1000 
parts  of  water  in  the  dye-bath;  and  for  water  of  10  degrees  to 
15  degrees  hardness  3  parts  of  acetic  acid  should  be  added.  The 
best  and  most  practical  way,  perhaps,  is  to  add  acetic  acid  to  the 
dye-bath  until  a  test-paper  of  blue  litmus  is  distinctly  reddened. 
Acetic  acid  is  furthermore  added  to  the  dye-bath  for  the  purpose 
of  more  thoroughly  exhausting  the  coloring-matter,  but  the 
addition  of  the  acid  in  this  case  should  not  be  made  until  near  the 
end  of  the  dyeing  operation,  in  order  to  prevent  unevenness. 


1 88  DYEING   AND    TEXTILE   CHEMISTRY. 

The  alizarins,  as  a  rule,  exhaust  quite  well  and  many  of  them  will 
not  require  any  acid  at  all,  especially  when  light  shades  are  dyed. 
The  initial  temperature  of  the  alizarin  dye-bath  should  be  quite 
low  (100°  F.  or  even  lower),  and  the  elevation  of  the  temperature 
to  the  boil  should  be  gradual  in  order  to  have  the  dyeing  even 
and  well  penetrated.  The  color-lake  does  not  develop  fully  until 
after  boiling  for  some  time,  hence  it  requires  a  longer  time,  as  a 
rule,  to  dye  alizarins  than  it  does  acid  colors  on  wool.  In  dyeing 
the  after-mordanted  alizarins,  it  is  usually  the  plan  to  add  the 
mordant  to  the  dye-bath  after  the  dyeing  is  completed;  for  this 
purpose,  the  dye-bath  should  be  very  well  exhausted,  otherwise 
the  mordanting  would  require  a  fresh  bath.  At  times,  where 
light  shades  are  being  dyed,  the  mordant  and  the  dyestuff  (both 
being  in  small  quantities)  may  be  added  to  the  bath  at  once,  and 
the  mordanting  and  dyeing  take  place  simultaneously.  There 
is  a  preparation  known  as  "  Metachrome"  mordant  which  consists 
essentially  of  chrome  and  ammonium  sulphate,  which  is  used 
together  with  certain  alizarins  for  dyeing  in  a  single  bath.  The 
presence  of  the  ammonium  sulphate  prevents  the  formation  of  the 
color-lake  before  the  dye-bath  has  reached  the  boil,  and  by  that 
time  most  of  the  chrome  will  have  been  absorbed  by  the  fibre. 
This  process  with  some  modifications  has  lately  become  of 
considerable  practical  value  for  the  dyeing  of  worsted  yarns, 
ammonium  acetate  being  used  in  conjunction  with  chrome  in  the 
dye-bath.  Only  certain  of  the  mordant  colors  are  applicable; 
these  are  sold  as  "chromate  "  dyes,  etc.  Where  very  bright  colors 
are  desired,  as  with  reds,  blues,  and  yellows,  chrome  cannot 
be  used  as  the  mordant,  but  alum  or  stannous  chloride  may  be 
employed.  Alum  is  used  to  quite  an  extent  for  certain  shades, 
but  as  the  colors  obtained  on  a  tin  mordant  are  not  as  fast  and 
as  the  tin  mordant  makes  the  wool  harsh  and  brittle,  it  is  very 
little  used  in  practice.  In  order  to  obtain  as  bright  and  clear 
colors  as  possible  with  the  alizarin  dyes,  it  is  necessary  that  the 
water  and  the  chemicals  employed  both  for  mordanting  and  dye- 
ing should  be  free  from  any  trace  of  iron,  as  the  presence  of  this 
metal  causes  a  saddening  of  the  color. 


APPLICATION  OF  MORDANT  DYES   TO   WOOL. 


189 


3.   List  of  the  Principal  Mordant  Dyes. 

(a)  APPLICABLE  TO  PREVIOUSLY  MORDANTED  WOOL. 


Alizarin. 

Alizarin  Black  B,  R,  2R,  and  V. 
Alizarin  Blue  (all  brands). 
Alizarin  Blue  Black  W  and  SW. 
Alizarin  Blue  S  (all  brands). 
Alizarin  Bordeaux. 
Alizarin  Brown  (all  brands). 
Alizarin  Chrome  Black  W. 
Alizarin  Cyanine  (all  brands). 
Alizarin  Dark   Blue   SW,   and   2W, 

and  S. 

Alizarin  Gray  G  and  R. 
Alizarin  Green  SW  and  S. 
Alizarin  Indigo  SW  and  SMW. 
Alizarin  Maroon. 
Alizarin  Reds  (pastes). 
Alizarin  Viridine  FF  and  DG. 
Alizarin  Yellow  FS. 
Alizarin  Yellow  N  powder. 
Anthracene  Blue. 
Anthracene  Brown  (all  brands). 
Anthracene  Dark  Blue  W. 
Anthracyl  Blue  G  and  R. 
Azo  Chromine  G. 
Blue  PRC. 


Chromazurine  S 

Chrome  Blue. 

Chrome  Brown. 

Chromocyanine  B  and  V. 

Cloth  Brown. 

Coelestine  Blue  B. 

Coeruleine. 

Cceruleine  S  in  paste. 

Coreine  2R,  AB,  and  AR. 

Delphine  Blue. 

Diamond  Brown  paste. 

Dioxine. 

Gallamine  Blue. 

Gallanil  Indigo  PS 

Gallocyanine. 

Galloflavine. 

Gallozine  A. 

Gambine  G  and  R. 

Phenocyanine  B  and  VS. 

Prune. 

Resoflavine. 

Rufigallol. 

Sulphamine. 

Sulphamine  Brown  A  and  B. 


(b)  SUITABLE  FOR  AFTER-MORDANTING. 


Acid  Alizarin  Black. 

Acid  Alizarin  Blue  BB  and  GR. 

Acid  Alizarin  Brown  B. 

Acid  Alizarin  Gray. 

Acid  Alizarin  Green. 

Acid  Alizarin  Grenat. 

Acid  Alizarin  Yellow. 

Acid  Anthracene  Brown  R,  T,  and  W. 

Acid  Chrome  Black  B  and  G. 

Alizarin  Cyanine  Green. 

Anthracene  Acid  Brown  (all  brands). 

Anthracene  Chrome  Black. 


Chrome  Black  B  and  T. 
Chrome  Fast  Black  B. 
Chrome  Fast  Black  F,  R,  and  BB. 
Chrome  Patent  Black. 
Diamond  Black  (all  brands). 
Diamond  Brown  3R. 
Diamond  Green  B. 
Domingo  Chrome  Black. 
Domingo  Violet  Black. 
Palatine  Chrome  Black  A. 
Palatine  Chrome  Brown  W. 


1 9o 


DYEING  AND    TEXTILE  CHEMISTRY. 


(c)  SUITABLE  FOR  BOTH  METHODS  OF  MORDANTING. 


Alizarin  Black  (all  brands). 

Alizarin  Blue  Black  B  and  36. 

Alizarin  Cyanine  Black  G. 

Alizarin  Fast  Black  T. 

Alizarin  Orange  paste  (all  brands). 

Alizarin  Red  PS  powder. 

Alizarin  Red  S  powder. 

Alizarin  Red  SB  and  W. 

Alizarin  Red  WS. 

Alizarin  Yellow  A,  C  paste. 

Alizarin  Yellow  paste. 

Alizarin  Yellow  2GW,  R,  RW,  2G, 

3G,  and  R. 
Anthracene  Red. 
Anthracene  Yellow  (all  brands). 
Anthracyl  Fast  Red. 
Brilliant  Alizarin  Blue  G  and  R. 
Brilliant  Alizarin  Cyanine  G  and  3G. 
Carbazol  Yellow  W. 
Chrome  Fast  Yellow  G. 
Chrome  Patent  Green. 
Chrome  Yellow  (all  brands). 
Cloth  Orange. 


Cloth  Red  (all  brands). 

Cloth  Scarlet. 

Diamond  Flavine  G. 

Diamond  Orange  paste. 

Diamond  Yellow  G  paste. 

Domingo  Chrome  Red. 

Domingo  Chrome  Yellow. 

Fast  Brown. 

Fast  Mordant  Yellow. 

Gallanil  Violet. 

Galleine. 

Indochromine. 

Metachrome  Brown  B. 

Milling  Brown  B  and  G. 

Milling  Orange. 

Milling  Red. 

Milling  Yellow. 

Mordant  Yellow  G,  R,  and  O. 

Salicine  Red. 

Salicine  Yellow  G  and  2G. 

Wool  Red. 

Wool  Yellow. 


(d)  SUITABLE  FOR  DYEING  IN  AN  ACID  BATH  WITHOUT  AFTER-CHROMING. 


Alizarin  Cyanine  Green. 
Alizarin  Heliotrope. 
Alizarin  Irisol. 
Alizarin  Pure  Blue. 
Alizarin  Saphirlol. 


Diamond  Brown  3R. 
Fast  Green  G. 
Milling  Green  S. 
Naphthol  Green  B. 


(e)  CHROME  DEVELOPED  DYESTUFFS. 


Acid  Alizarin  Black  R. 
Azo  Fuchsine  B  and  G. 
Azo  Rubine. 
Carmoisine  B 


Chrome  Brown  BO  and  RO. 
Chromogen  I. 
Chromotrop  (all  brands). 
Florida  Red. 


APPLICATION  OF  MORDANT  DYES  TO   WOOL.  igi 

SAMPLES. 

328.  Alizarin  Blue  on  wool;  showing  general  method  of  dyeing. 

329.  Effect  of  iron  in  mordant  bath. 

330.  Effect  of  iron  mordant  on  color. 

331.  Effect  of  iron  in  dye-bath. 

332.  Wool  mordanted  with  chrome. 

333.  Alizarin  Red  on  a  chrome  mordant. 

334.  Wool  mordanted  with  alum. 

335.  Alizarin  Red  on  alum  mordant. 

336.  Wool  mordanted  with  copperas. 

337.  Alizarin  Red  on  a  copperas  mordant. 

338.  Wool  mordanted  with  bluestone. 

339.  Alizarin  Red  on  a  bluestone  mordant. 

340.  Wool  mordanted  with  stannous  chloride. 

341 .  Alizarin  Red  on  a  tin  mordant. 

342  a.  Anthracene  Yellow  on  wool  before  chroming. 
342b.  Anthracene  Yellow  after  chroming. 
343 a.  Acid  Alizarin  Green  before  chroming. 
343b.  Acid  Alizarin  Green  after  chroming. 

344.  Diamond  Black  GA  before  chroming. 

345.  Diamond  Black  GA  after  chroming. 

346.  Diamond  Yellow  before  chroming. 

347.  Diamond  Yellow  after  chroming. 

QUIZ  16. 

471 .  What  is  the  most  generally  used  mordant  on  wool  ?    How  is  it  applied 
to  the  fibre? 

472.  Give  the  general  method  for  dyeing  the  alizarin  colors  on  a  chrome 
mordant. 

473.  What  is  chrome?     Of  what  acid  is  it  a  salt?     In  what  condition  is 
the  mordant  eventually  produced  on  the  fibre  ? 

474.  How  is  the  reduction  of  the  chrome  brought  about  in  the  mordanting 
bath? 

475.  What  is  tartar?    How  does  it  act  as  an  assistant  in  mordanting  with 
chrome  ? 

476.  How  do  iron  salts  in  the  mordant  affect  the  colors  of  alizarin  dyes? 
Should  iron  be  present  in  the  dye-bath  ? 

477.  What  are  the  five  principal  mordants  which  may  be  used  on  wool? 
Of  what  metals  are  they  derivatives  ? 

478.  What  color  does  a  chrome  mordant  give  on  wool?    Why  should  not 
chrome  mordanted  wool  be  exposed  for  any  length  of  time  to  strong  light  before 
dyeing? 


IQ2  DYEING  AND    TEXTILE  CHEMISTRY. 

479.  What  color  does  Alizarin  Red  give  with  a  chrome  mordant?    With  a 
copperas  mordant  ? 

480.  What  is  copperas?    How  is  this  mordant  applied  to  wool?    In  what 
condition  would  the  mordant  be  present  in  the  fibre?    What  color  does  the 
mordant  give  to  the  wool  ? 

481.  What  is  bluestone  ?    How  is  it  applied  to  wool  as  a  mordant  ?    What 
color  does  it  give  to  the  fibre? 

482.  What  color  does  Alizarin  Red  give  with  a  copper  mordant  ?     Compare 
this  color  with  that  obtained  with  chrome. 

483.  What  is  the  tin  mordant  used  on  wool?     How  is  it  applied?    What 
color  does  it  give  to  the  fibre  ?    How  does  it  affect  the  physical  properties  of  the 
fibre? 

484.  What  color  does  Alizarin  Red  give  with  a  tin  mordant?    How  does 
this  color  compare  with  that  obtained  with  chrome  ? 

485.  How  is  the  process  of  after-mordanting  carried  out?     How  many 
baths  are  required  ? 

486.  What  effect  does  the  after-chroming  process  have  on  the  color  of 
anthracene  yellow  ? 

487.  What  kind  of  alizarin  dyes  are  best  adapted  for  the  after-chroming 
process  ?    In  what  form  do  such  dyes  usually  come,  and  of  what  do  they  con- 
sist?   How  do  they  compare  with  ordinary  alizarins  as  to  solubility? 

488.  How  does  the  after-chroming  affect  the  color  of  Acid  Alizarin  Green? 

489.  Describe  the  method  of  dyeing  Diamond  Black.     What  are  the  charac- 
teristics of  this  color  ? 

490.  Give  the  process  of  dyeing  Diamond  Yellow.     What  is  the  fastness 
of  this  color  to  washing  and  acids  ? 

491 .  In  using  a  chrome  mordant  bath  as  a  standing  kettle  how  much  chrome 
and  tartar  must  be  added  for  successive  lots  ? 

492.  Why  should  wool  be  well  washed  after  mordanting?    What  would 
be  the  result  if  this  were  not  done  ? 

493.  What  is  the  proper  amount  of  chrome  to  use  in  preparing  a  mordant 
bath  for  a  full  shade  ?     Is  this  amount  necessary  for  lighter  shades  ? 

494.  Why  is  it  not  desirable  to  employ  larger  amounts  than  3  per  cent,  of 
chrome  in  mordanting  wool  ?     What  is  the  effect  of  too  much  chrome  on  the 
fibre  itself? 

495.  What  other  substances  besides  tartar  may  be  used  as  assistants  in  the 
mordant  bath  ?    What  are  lactoline,  lignorosin,  and  tartar  substitute  ? 

496.  Which  assistant  furnishes  the  best  results?    For  what  colors  is  lactic 
acid  a  good  assistant  ?    What  is  the  advantage  of  lactic  acid  as  compared  with 
tartar?    What  color  does  the  wool  acquire  with  lactic  acid,  and  why? 

497-  Why  is  calcium  acetate  often  added  to  the  dye-bath  with  alizarin 
colors  ?    Why  is  hard  water  beneficial  when  dyeing  alizarin  colors  ? 


APPLICATION  OF  MORDANT  DYES   TO   WOOL.  1 93 

498.  In  using  hard  water  with  alizarin  colors  why  is  acetic  acid  used  in 
the  dye-bath?    What  proportion  of  acetic  acid  should  be  added  to  water  of 
10  degrees  hardness ?    What  is  meant  by  a  degree  of  hardness?    What  is  the 
most  practical  method  of  knowing  the  proper  amount  of  acetic  acid  to  use  in 
the  bath? 

499.  What  further  use  has  acetic  acid  in  dyeing  alizarin  colors  besides  the 
formation  of  calcium  acetate  with  the  lime  salts  in  the  water? 

500 .  Do  the  alizarin  dyes  exhaust  well  ?     How  may  the  degree  of  exhaustion 
be  increased  ?     How  is  unevenness  prevented  ? 

501 .  Why  should  the  alizarin  dye-bath  be  started  at  a  low  temperature,  and 
why  is  a  good  boiling  necessary  ? 

502.  Under  what  conditions  may  the  mordant  and  dyestuff  be  added 
together  to  the  dye-bath  ?    What  is  metachrome  mordant  and  how  is  it  used  ? 

503.  When  especially  bright  colors  are  to  be  obtained  with  alizarins  what 
mordants  must  be  employed  ?     What  precautions  should  be  taken  in  order  to 
obtain  clear  bright  colors  ? 

504.  What  is  meant  by  saddening  a  color,  and  how  may  this  be  done  in  the 
case  of  alizarin  dyes  ? 


SECTION  XVII. 
DEVELOPED  DYES  ON  COTTON  AND  SILK. 

Experiment  103.  General  Method  of  Applying  Developed 
Dyes.  —  Certain  of  the  substantive  dyes  may  be  applied  to  cotton 
in  the  usual  manner,  and  then  changed  by  chemical  treatment  into 
other  dyestuffs  which  may  be  of  a  totally  different  color,  and  are 
frequently  much  faster  or  deeper  in  shade  than  the  original  color 
from  which  they  have  been  derived.  In  other  words,  the  dyestuff 
is  built  up  within  the  fibre  itself  just  as  ordinary  dyesmffs  are 
formed  without  reference  to  the  fibre.  This  class  of  substantive 
dyes  is  known  as  the  "developed"  or  "diazotized"  colors,  from 
the  chemical  processes  through  which  they  pass.  These  dyes 
form  a  rather  important  class  of  colors,  the  value  and  adaptability 
of  which  are  constantly  growing.  Primuline  was  the  first  of 
these  dyes  discovered,  and  is  still  the  most  important  one  in  use 
and  may  be  taken  as  the  type  of  the  entire  class.  Dye  a  test- 
skein  of  cotton  yarn  in  a  bath  containing  6  per  cent,  of  Primuline, 
20  per  cent,  of  salt,  and  i  per  cent,  of  soda  ash;  enter  at  140°  F., 
gradually  raise  to  the  boil  and  dye  at  that  temperature  for  one- 
half  hour.  It  will  be  noticed  that  this  is  simply  the  general 
method  for  applying  substantive  dyes,  and  that  the  color  obtained 
is  yellow  (348).  Rinse  the  skein  in  fresh  water  and  pass  into  a 
cold  bath  containing  5  per  cent,  of  sodium  nitrite  and  6  per  cent, 
of  sulphuric  acid;  work  for  about  10  minutes.  It  will  be  noted 
that  the  yellow  color  of  the  dye  is  altered  to  a  brownish  yellow 
(349)  by  this  treatment,  and  if  the  odor  of  the  bath  is  observed 
the  presence  of  nitrous  acid  will  be  noted.  Rinse  the  skein  with 
cold  water,  and  immediately  pass  into  a  third  bath  containing 
2  per  cent,  of  beta-naphthol  solution;  work  cold  for  15  minutes, 
then  wash  well  and  dry  (350).  When  placed  in  the  third  bath  it 
will  be  noticed  that  the  skein  turns  a  bright  red  color,  which  is  due 

194 


DEVELOPED  DYES  ON  COTTON  AND  SILK.  195 

to  the  new  dyestuff  which  has  thus  been  formed  within  the  fibre. 
In  the  first  bath  the  Primuline  acts  merely  as  a  substantive  dye, 
and  gives  a  yellow  color  which  possesses  no  fastness  and  is  unim- 
portant.    The  second  solution  is  termed  the  "diazotizing"  bath. 
The  action  of  the  sodium  nitrite  on  the  sulphuric  acid  is  to  liberate 
nitrous  acid  and  form  sodium  sulphate;  the  nitrous  acid   acts 
on  the  dyestuff  in  such  a  manner  that  the  amido  groups  (NH2) 
present  are  changed  into  what  are  known  as  "diazo"  groups, 
N  :  N.     This  diazo   group  combines  with   the   sulphuric   acid 
present  in  the  bath  and  forms  primuline-diazo-sulphate.     The 
diazo  body  is  quite  unstable,  hence  the  bath  must  be  employed 
cold,  and  the  cotton  must  be  passed  from  this  bath  as  soon  as 
possible  into  the  third  bath,  for  if  the  diazotized  material  is 
allowed  to  stand  for  any  length  of  time,  especially  if  exposed  to 
strong  light,  the  diazo  body  will  decompose  and  the  eventual 
color  will  be  spoiled.     The  diazotizing  bath  should  smell  dis- 
tinctly of  nitrous  acid,  and  if  such  is  not  the  case,  more  sodium 
nitrite  and  acid  should  be  added.     Care  should  be  taken  that  this 
bath  does  not  become  heated  by  leaky  steam-pipes,  etc.     Some- 
times, in  fact,  ice  is  added  to  this  bath  for  the  purpose  of  keeping 
the  tamper ature  down  (hence  these  colors  are  sometimes  spoken 
of  as  " ice-colors");  but  if  the  bath  is  kept  at  the  ordinary  tem- 
perature of  water  (about  60  to  70°  F.)  no  artificial  cooling  is  neces- 
sary.    The  third  bath  is  termed  the  "developing"  bath,  and  the 
beta-naphthol  (or  other  like  body)  is  spoken  of  as  the  "  developer." 
Its  function  is  to  combine  with  the  unstable  diazo  body  to  give 
the  new  and  permanent  coloring-matter.     This  bath  should  also 
be  cold,  otherwise  the  diazo  body  on  first  entering  the  bath  will 
be  decomposed  before  it  has  had  a  chance  to  become  fixed  by  the 
developer.     Beta-naphthol  is  not  very  soluble  in  water  (especially 
cold  water),  hence,  before  adding  it  to  the  bath  it  is  advisable  to 
dissolve  it  in  a  little  hot  water  together  with  its  weight  of  soda 
ash,  or  caustic  soda,  and  add  this  solution  to  the  developing  bath. 
Experiment  104.   Showing  the  Action  of  Heat  on  the  Diazo 
Body.  —  Dye  a  skein  of  cotton  yarn  as  before  with  6  per  cent, 
of  Primuline;  rinse  and  diazotize  in  a  bath  containing  5  per  cent. 


196  DYEING  AND   TEXTILE  CHEMISTRY. 

of  sodium  nitrite  and  6  per  cent,  of  sulphuric  acid;  work  for 
10  minutes  at  a  temperature  of  180°  F.,  then  rinse,  and  pass  into 
the  developing  bath  prepared  as  above  described;  work  cold  for 
10  minutes,  then  wash  and  dry  (351).  Compare  the  color  obtained 
on  this  skein  with  that  on  the  one  in  the  previous  experiment. 
Dye  another  skein  of  cotton  yarn  with  6  per  cent,  of  Primuline  as 
before,  and  diazotize  cold  as  in  the  previous  experiment.  Then 
wash  the  skein  in  hot  water  for  10  minutes,  and  afterwards 
develop  as  already  described  in  the  beta-naphthol  bath  cold  for 
10  minutes  (352).  Notice  the  influence  of  the  hot  washing  on 
the  eventual  color.  Dye  another  skein  with  6  per  cent,  of  Primu- 
line as  before;  diazotize  cold,  and  expose  to  the  air  for  several 
hours  ;  then  develop  as  usual  in  the  beta-naphthol  bath  cold  for 
10  minutes  (353).  Notice  the  influence  of  the  long  exposure  on 
the  color. 

Experiment  105.  Developed  Black  on  Cotton.  —  Although 
there  are  several  black  dyes  among  the  substantive  colors,  yet 
they  do  not  yield  very  satisfactory  colors  either  as  regards  depth 
of  tone  or  fastness  to  bleeding  when  dyed  directly.  Some  of 
these  may  be  diazotized  and  developed,  however,  and  so  produce 
black  colors  of  great  beauty  and  fastness.  Dye  a  skein  of  cotton 
yarn  in  a  bath  containing  6  per  cent,  of  Diamine  Black  BH,  20  per 
cent,  of  common  salt,  and  i  per  cent,  of  soda  ash;  enter  at  140°  F., 
gradually  raise  to  the  boil,  and  dye  at  that  temperature  for  one- 
half  hour;  rinse  (354),  and  diazotize  as  usual,  and  then  develop 
with  2  per  cent.'of  phenylene-diamine  in  same  manner  as  employed 
for  beta-naphthol;  wash  well  and  dry  (355).  Phenylene-diamine 
is  best  dissolved  previously  to  its  addition  to  the  bath  in  a  little 
soda  ash.  Test  the  black  thus  obtained  for  fastness  to  washing 
and  cross-dyeing.  Also  preserve  a  sample  of  the  color  before 
diazotization,  and  compare  it  in  tone  of  color  with  the  developed 
dyeing;  also  test  the  fastness  of  the  direct  dyeing  to  washing  (356) 
and  cross-dyeing  (357),  and  compare  these  results  with  those  for 
the  developed  dyeing. 

Experiment  106.  Dyeing  Primuline  on  Silk.  —  Some  of  the 
developed  dyes  are  very  suitable  for  the  dyeing  of  fast  colors  on 


DEVELOPED  DYES  ON   COTTON  AND   SILK.  197 

silk.  Dye  a  skein  of  silk  in  a  bath  containing  10  per  cent,  of 
glaubersalt  and  10  per  cent,  of  Primuline;  enter  at  140°  F.,  and 
gradually  bring  to  the  boil  and  dye  at  that  temperature  for  one- 
half  hour;  rinse,  and  diazotize  and  develop  with  beta-naphthol 
as  already  described  in  the  foregoing  experiments  (358).  This 
should  give  a  good  heavy  red  which  is  fast  to  washing  and 
water. 

Experiment  107.  Dyeing  a  Developed  Black  on  Silk.  —  Dye  a 
skein  of  silk  yarn  in  a  bath  containing  10  per  cent,  of  glaubersalt 
and  10  per  cent. of  Zambesi  Black  D  in  the  usual  manner;  diazotize 
and  develop  with  3  per  cent,  of  toluylene-diamine.  Wash  well 
and  dry  (559).  Test  this  color  for  fastness  to  washing  and 

water. 

NOTES.   , 

i.   The   Production  of    Developed   Colors   on   Cotton.  —  The 

defect  of  the  substantive  dyes  on  cotton  is  their  liability  to  bleed 
when  washed,  although  this  may  be  remedied  in  some  cases  by 
an  after-treatment  with  certain  metallic  salts;  still  faster  dyeings 
may  usually  be  obtained  by  the  diazotizing  and  developing 
process.  This  process  is  more  especially  employed  for  the  pro- 
duction of  primuline  red  as  a  substitute  for  the  more  expensive 
Turkey-red,  and  for  the  production  of  fast  blacks;  the  other  colors 
are  not  so  much  used.  The  developing  process  not  only  materially 
increases  the  fastness  of  the  colors  to  washing  and  acids  but  it 
also  greatly  increases  the  intensity  of  the  shade.  It  has  already 
been  said,  in  fact,  that  the  substantive  colors  do  not  yield  very 
deep  shades  on  cotton,  even  when  large  amounts  of  dyestuff  are 
used  in  the  bath;  in  many  cases  the  blacks  when  dyed  direct 
give  only  dark  blue  or  slate  colors,  and  only  produce  a  deep  black 
on  being  diazotized  and  developed.  Not  all  of  the  substantive 
dyes  may  be  developed,  but  a  sufficient  number  of  them  are 
susceptible  to  this  treatment  to  give  a  wide  range  of  shades,  and 
there  are  a  number  of  the  dyes  which  diazotizing  does  not  affect, 
and  which  may  in  consequence  be  used  for  purposes  of  shading, 
being  added  directly  to  the  same  dye-bath  as  the  developed 
color. 


198  DYEING  AND    TEXTILE  CHEMISTRY. 

It  must  be  borne  in  mind  that  developed  colors  require  three 
different  operations  and  as  many  different  baths;  this  necessitates, 
of  course,  a  triple  handling  of  the  cotton  and  therefore  a  greater 
expense  than  when  dyeing  the  substantive  colors  alone.  There 
is  nothing  different  in  the  first  dyeing  process  of  the  developed 
colors  beyond  that  of  the  ordinary  substantive  dyes,  which  have 
already  been  discussed.  The  second  operation,  that  of  diazo- 
tizing,  is  the  same  for  all  the  developed  colors,  and  consists  in 
working  the  dyed  and  rinsed  cotton  in  a  cold  bath  containing 
sodium  nitrite  and  hydrochloric  acid;  the  operation  requires  only 
10  to  15  minutes.  After  diazotizing  it  is  well  to  rinse  the  goods 
in  water  slightly  acidulated  with  hydrochloric  acid.  The  third 
operation,  that  of  developing,  is  also  done  in  a  cold  bath  and 
requires  only  from  10  to  15  minutes;  the  kind  of  developer 
used  depending  on  the  dyestuff  employed  and  the  color  desired. 
A  diazotizing  bath  for  10  pounds  of  cotton  can  be  pre- 
pared with  J  Ib.  sodium  nitrite  and  £  Ib.  hydrochloric  acid 
(of  32°  Tw.);  sulphuric  acid  may  be  used  in  place  of 
hydrochloric,  in  which  case  only  J  Ib.  of  acid  (of  168°  Tw.) 
is  employed.  In  preparing  the  bath  the  nitrite  should  first 
be  dissolved  in  some  water,  added  to  the  bath,  after  which 
the  acid  is  added.  For  standing  baths  only  one-third  of  the 
above-mentioned  quantities  is  used.  In  order  to  ascertain  if 
the  diazotizing  bath  is  still  active,  dip  into  it  a  piece  of  paper 
impregnated  with  starch  paste  and  potassium  iodide,  which 
should  at  once  turn  blue.  When  working  the  bath  it  should 
smell  distinctly  of  nitrous  acid,  though  the  odor  should  not  be  too 
pungent,  which  would  indicate  an  excess  of  nitrite.  This  is  not 
necessarily  injurious,  but  should  be  avoided  for  reasons  of 
economy.  The  diazotizing  is  best  conducted  in  wooden  vessels, 
though  when  dyeing  in  machines  the  diazotizing  and  developing 
may  take  place  in  copper  vessels.  It  is  not  necessary  to  hydro- 
extract  or  wring  out  after  diazotizing;  the  goods  are  allowed  to 
drain,  are  then  rinsed  slightly  in  water  acidulated  with  i  pint  of 
hydrochloric  acid  to  100  gallons,  and  then  entered  directly  into 
the  developing  bath.  It  is  also  important  to  remember  that  the 


DEVELOPED   DYES  ON  COTTON  AND  SILK.  199 

diazotized  goods  should  not  be  left  standing  for  any  length  of 
time,  but  the  rinsing  and  developing  should  proceed  immediately 
after  the  diazotizing.  Especial  care  should  be  taken  not  to 
expose  the  diazotized  color  to  glaring  light  or  to  any  source  of 
heat.  The  developing  bath  is  prepared  with  cold  water  and  the 
requisite  amount  of  developer  in  solution.  The  goods  are  turned 
a  few  times  in  this  bath,  then  taken  out  and  rinsed  off.  The 
beta-naphthol  solution  for  developing  may  be  prepared  con- 
veniently by  dissolving  7  Ibs.  3  ozs.  of  beta-naphthol  and 
6  Ibs.  caustic  soda  (of  77°  Tw.)  in  10  gallons  of  boiling  water; 
for  each  10  Ibs.  of  cotton  developed  use  ij  pints  of  this  solu- 
tion. For  phenylene-diamine  or  toluylene-diamine,  dissolve 
4j  Ibs.  of  the  salt  with  ij  Ibs.  of  soda  ash  in  10  gallons 
of  boiling  water,  and  ij  pints  of  this  solution  is  sufficient  for 
10  Ibs.  of  cotton.  If  the  baths  are  used  repeatedly,  the  above 
quantities  are  used  for  the  first  two  to  three  lots,  after  which  only 
three-fourths  the  amounts  are  taken.  The  amount  of  water  in 
the  diazotizing  and  developing  baths  should  be  about  20  times 
the  weight  of  the  cotton.  An  addition  of  bluestone  to  the  diazo- 
tizing bath  increases  the  fastness  to  light  of  the  color  in  most 
cases;  for  such  purpose,  however,  it  is  best  to  give  an  after- 
treatment  with  bluestone  after  developing,  by  passing  the  goods 
through  a  cold  or  lukewarm  bath  containing  3  per  cent,  of  blue- 
stone  and  3  per  cent,  of  acetic  acid,  and  then  rinsing.  After 
development  or  after-treatment  the  cotton  is  usually  soaped  or 
oiled  for  the  purpose  of  softening.  Developed  dyeing  may  be 
topped  with  basic  dyes  in  the  same  manner  as  the  direct  dyeings 
with  substantive  colors. 

2.    List  of  the  Principal  Developed  Dyes. 
Diamine  Azo  Black.  Diaminogene  Blue. 

Diamine  Azo  Blue.  Diaminogene  extra. 

Diamine  Black.  Dianil  Dark  Blue. 

Diamine  Blue  Black.  Diazo  Black  (all  brands). 

Diamine  Bronze.  Diazo  Blue. 

Diamine  Brown.  Diazo  Blue  Black. 

Diamine  Catechine.  Diazo  Bordeaux. 

Diaminogene.  Diazo  Brown. 


200  DYEING  AND    TEXTILE   CHEMISTRY. 

LIST  OF  THE  PRINCIPAL  DEVELOPED  DYES.— Continued. 

Diazo  Brilliant  Black.  Oxamine  Black  A. 

Diazo  Dark  Blue.  Oxamine  Violet. 

Diazo  Fast  Black.  Polychromine  A  and  B. 

Diazo  Indigo  Blue.  Primuline  (all  brands). 

Diazo  Rubine.  Thiochromogene. 

Diazurine  B.  Toluylene  Blue  Black. 

Diazyl  Black  Zambesi  Black. 

Direct  Indigo  Blue.  Zambesi  Blue. 

Hessian  Bordeaux.  Zambesi  Brown. 

Indigo  Blue  B.  Zambesi  Gray. 

Melanogen  Blue  BH.  Zambesi  Indigo  Blue. 
Melantherine. 

SAMPLES. 

348.  Primuline  before  diazotizing. 

349.  Primuline  after  diazotizing. 

350.  Primuline  after  development. 

351.  Primuline  when  diazotized  in  hot  bath. 

352.  Diazotized  Primuline  heated  before  development. 

353.  Diazotized  Primuline  exposed  to  light. 
354-  Diamine  Black  BH  before  dyed  direct. 

355.  Diamine  Black  BH  diazotized  and  developed. 

356.  Washing  test  for  diazotized  black,  and  before  diazotizing. 

357.  Cross-dye  test  for  diazotized  black,  and  before  diazotizing. 

358.  Primuline  on  silk. 

359.  Developed  black  on  silk  with  Zambesi  Black  D. 

QUIZ  17. 

505.  What  are  developed  or  diazotized  colors?    To  what  general  class  of 
dyes  do  they  belong? 

.  506.   What  was  the  first  developed  dyestuff  discovered?    What  is  the 
general  principle  of  dyeing  the  developed  dyes  ? 

507.  What  color  does  Primuline  give  when  dyed  as  an  ordinary  substantive 
dye  ?     What  change  in  color  is  noticed  on  diazotizing  ?     On  developing  ? 

508.  Of  what  does  the  diazotizing  bath  consist?    To  what  is  the  odor  of 
this  bath  due  ?     What  chemical  reaction  takes  place  between  the  constituents 
of  this  bath? 

509.  What  is  the  "amido"  group?    What  is  the  action  of  nitrous  acid  on 
it  ?     What  is  the  * '  diazo  "  group  ? 

510.  Why  is  the  diazotizing  bath  used  cold?    Why  are  the  diazotized 
colors  sometimes  spoken  of  as  "ice  colors"? 


DEVELOPED   DYES  ON  COTTON  AND  SILK.  2OI 

511.  What  is  the  function  of  the  developing  bath  ?     How  is  the  developing 
bath  with  beta-naphthol  prepared  ? 

512.  How  long  does  the  treatment  last  in  the  diazotizing  and  developing 
baths?     Why  should  development  immediately  follow  diazotizing? 

513.  What  is  the  effect  of  heating  the  diazotizing  bath?     Of  heating  the 
diazotized  color  before  development? 

514.  What  is  the  effect  of  exposing  the  diazotized  color  to  the  action  of  light 
and  air  for  some  time  previous  to  development  ? 

515.  Can  a  satisfactory  black  color,  as  a  rule,  be  obtained  with  substantive 
dyes  directly?     Describe  how  a  good  black  may  be  obtained  with  Diamine 
Black  BH.     What  developer  is  employed? 

516.  What  is  the  fastness  of  the  developed  Diamine  Black  to  washing  and 
cross-dyeing  ?     How  were  these  tests  made  ? 

517.  Give  the  method  for  dyeing  Primuline  red  on  silk.     Is  this  red  fast  to 
washing  and  water? 

518.  How  did  you  produce  a  developed  black  on  silk  ?    What  dyestuff  and 
developer  were  used?     What  was  the  fastness  of  this  color  to  washing  and 
water  ? 

519.  What  is  the  general  object  of  diazotizing  and  developing  the  substan- 
tive colors  ?    What  are  the  principal  colors  obtained  in  this  method  ? 

520.  May  all  substantive  dyes  be  developed?     How  may  the  developed 
dyeings  be  shaded  ? 

521.  How  many  operations  and  baths  do  the  developed  colors  require? 
Why  are  they  more  expensive  than  substantive  colors  dyed  direct  ? 

522.  Does  the  diazotizing  process  differ  with  different  colors?     How  should 
the  dyed  goods  be  rinsed  after  diazotizing  ?     On  what  considerations  does  the 
selection  of  the  proper  developer  depend  ? 

523.  How  would  you  prepare  a   fresh   diazotizing   bath   for   10   Ibs.    of 
cotton  yarn?     What  amount  of  chemicals  would  you  add  to  a  standing 
kettle? 

524.  What  acids  may  be  used  in  the  diazotizing  bath,  and  what  is  the  ratio 
of  their  proportions? 

525.  How  would  you  test  the  diazotizing  bath  to  ascertain  if  it  still  contained 
nitrous  acid?     On  what  chemical  principle  does  this  reaction  depend? 

526.  In  what  kind  of  vats  is  it  best  to  conduct  the  diazotizing  process? 
May  copper  vessels  be  employed  ? 

527.  How  would  you  prepare  the  acid  wash  water  for  rinsing  off  the  diazo- 
tized color  before  development  ? 

528.  What  precautions  should  be  taken  with  the  diazotized  color  previous 
to  development  in  order  to  obtain  good  results  ? 

529.  How  would  you  prepare  the  beta-naphthol  solution  of  developer,  and 
what  quantity  of  this  solution  would  be  needed  for  10  Ibs.  of  cotton  ? 


202  DYEING  AND    TEXTILE  CHEMISTRY. 

530.  How  are  the  solutions  of  phenylene-  and  toluylene-diamine  prepared 
for  a  developer?    What  quantity  is  needed  for  10  Ibs.  of  cotton? 

531.  May  the  developing  bath  be  used  as  a  standing  kettle?    If  so,  what 
proportional  amounts  of  developer  are  taken  for  succeeding  baths  ? 

532.  What  proportion  of  water  should  be  employed  in  the  diazotizing  and 
developing  baths  ? 

533.  How  may  an  after-treatment  with  bluestone  be  given  to  developed 
dyeings  ?     May  developed  dyeings  be  topped  with  basic  dyes,  and  if  so,  in 
what  manner? 


SECTION  XVIII. 
SULPHUR  DYES  ON  COTTON. 

Experiment  108.   General  Method  of  Applying  Sulphur  Dyes.  — 

Prepare  a  bath  containing  5  per  cent,  of  Immedial  Brown  B,  5  per 
cent,  of  sodium  sulphide,  5  per  cent,  of  soda  ash,  and  25  per  cent, 
of  common-salt.  Dye  a  skein  of  cotton  yarn  in  this  bath,  entering 
at  140°  F.,  gradually  raise  to  the  boil,  and  dye  at  that  temperature 
for  one-half  hour;  wash  and  dry  (360).  It  will  be  noticed  that 
the  dye-bath  does  not  exhaust  very  well,  so  dye  a  second  skein 
(361)  of  cotton  yarn  in  the  same  bath  without  adding  any  further 
dyestuff  or  chemicals,  only  diluting  the  bath  to  its  original  vol- 
ume with  water.  Also  dye  a  third  skein  (362)  in  the  same  manner. 
Compare  the  colors  on  the  three  skeins,  the  gradation  of  which 
will  show  the  comparative  exhaustion  of  the  bath. 

Experiment  109.  After-treatment  of  Sulphur  Dyes  with 
Chrome.  —  An  after-treatment  with  chrome  is  sometimes  given 
in  order  to  obtain  a  faster  color.  Dye  a  skein  of  cotton  yarn  with 
5  per  cent,  of  Immedial  Brown  B  in  the  same  manner  as  above 
described;  squeeze,  rinse,  and  treat  in  a  fresh  bath  containing 
2  per  cent,  of  chrome  and  3  per  cent,  of  acetic  acid;  boil  for  15 
minutes;  wash  well  and  dry  (363).  Compare  the  color  of  this 
skein  with  the  corresponding  one  in  the  previous  experiment  and 
note  the  effect  of  the  after-treatment  on  the  tone  of  the  color. 
Also  test  the  fastness  of  these  two  dyeings  to  washing  and  cross- 
dyeing  (364,  365,  366,  367). 

Experiment  no.  Obtaining  Black  with  Sulphur  Dyes.  —  Dye 
a  skein  of  cotton  yarn  in  a  bath  containing  15  per  cent,  of  Sulphur 
Black  A  extra,  15  per  cent,  of  sodium  sulphide,  5  per  cent,  of  soda 
ash,  and  50  per  cent,  of  common-salt;  enter  at  140°  F.,  gradually 
raise  to  the  boil,  and  dye  at  that  temperature  for  one-half  hour; 
wash  well,  and  treat  in  a  bath  containing  2  per  cent,  of  olive  oil 

203 


204  DYEING  AND    TEXTILE   CHEMISTRY. 

emulsion;  then  rinse  and  dry  (368).     Test  the  color  of  this  skein 
for  fastness  to  washing  (369)  and  cross-dyeing  (370)- 

Experiment  in.  Use  of  Autogene  Black.  —  This  sulphur  dye 
does  not  require  the  addition  of  sodium,  sulphide  to  the  bath. 
Dye  a  skein  of  cotton  yarn  in  a  bath  containing  50  per  cent,  of 
salt  and  15  per  cent,  of  Autogene  Black;  enter  at  140°  F., 
gradually  raise  to  the  boil,  and  dye  at  that  temperature  for  three- 
quarters  hour;  wash  well,  and  then  soap  in  a  warm  dilute  solution 
of  soap;  rinse  and  dry  (371).  This  black  gives  a  color  much 
resembling  Aniline  Black.  Test  the  fastness  of  the  color  to 
washing  (372)  and  cross-dyeing  (373).  Compare  the  color  of 
these  sulphur  blacks  with  that  obtained  with  developed  dyeings, 
and  also  compare  the  fastness  of  the  colors. 

NOTES. 

i.  Use  of  the  Sulphur  Dyes.  —  These  colors  belong  to  the 
general  group  of  substantive  cotton  dyes  and  are  of  rather  recent 
introduction.  They  are  so  called  because  they  consist  of  sulphur 
compounds,  and  are  dyed,  as  a  rule,  with  the  addition  of  sodium 
sulphide  to  the  bath.  The  first  of  these  dyes  was  discovered  in 
1867  by  two  French  chemists,  and  was  known  as  Cachou  de 
Laval;  it  was  prepared  by  fusing  wood  shavings  and  sawdust 
with  sodium  sulphide  or  sulphur.  •  As  it  had  but  little  tinctorial 
power  it  was  not  a  success  as  a  dyestuff.  During  the  past  decade, 
however,  a  large  nurhber  of  these  dyes  have  appeared  in  almost 
all  colors  with  the  exception  of  red,  and  even  during  the  past  year 
a  so-called  sulphur  red  dye  has  been  brought  out,  but  it  is  far 
from  being  a  pure  red  color.  We  have  sulphur  blacks,  browns, 
blues,  yellows,  and  greens.  The  sulphur  colors  are  especially 
remarkable  for  their  fastness  to  washing  and  even  fulling,  as  well 
as  acids  in  cross-dyeing.  They  also  furnish  deep,  heavy  shades 
on  cotton.  They  are  mostly  dyed  in  a  bath  containing  sodium 
sulphide,  soda  ash,  common-salt,  and  many  of  them  may  be  after- 
treated  with  chrome  or  bluestone  with  considerable  improvement 
as  to  their  fastness.  The  sodium  sulphide  is  for  the  purpose  of 
dissolving  and  in  some  cases  of  reducing  the  dyestuff  (in  the  case 


SULPHUR  DYES  ON  COTTON  205 

of  certain  blue  dyes) ;  the  soda  ash  is  for  the  purpose  of  correcting 
the  hardness  of  the  water  and  making  the  bath  alkaline,  as  the 
dyes  appear  to  work  better  in  an  alkaline  bath;  the  salt  is  added 
as  with  ordinary  substantive  dyes,  for  the  purpose  of  obtaining 
a  better  exhaustion  of  the  dye-bath.  In  some  cases  the  dyestuff 
itself  contains  sufficient  sodium  sulphide  to  dissolve  it  in  the  bath, 
and  consequently  none  need  be  added.  The  sulphur  dyes  are 
evidently  not  as  yet  distinct  chemical  bodies;  that  is  to  say,  the 
proper  tinctorial  principle  has  not  been  isolated  from  contaminat- 
ing by-products  in  their  manufacture,  and  consequently  it  takes 
a  relatively  large  amount  of  dyestuff  to  obtain  a  full  shade;  from 
10  to  15  per  cent.,  as  a  rule,  in  the  case  of  colors,  and  from  20  to 
30  per  cent,  for  blacks  being  required;  in  this  respect,  however, 
these  dyes  are  constantly  being  improved,  as  better  methods  of 
manufacture  are  devised.  At  first,  these  dyes  were  sold  usually 
in  the  form  of  irregular  lumps  which  rapidly  deteriorated  on 
exposure  to  air  and  dampness  with  liberation  of  sulphuretted 
hydrogen;  but  in  this  respect  there  has  been  much  improvement 
of  late  by  selling  the  dyes  in  powder  form  mixed  with  proper 
drying  substances  to  prevent  the  absorption  of  moisture  on 
exposure.  The  sulphur  dyes  exhaust  badly  and  require  a  large 
amount  of  salt  in  the  bath  where  heavy  shades  are  to  be  dyed. 

The  sulphur  dyes  are  best  dissolved  in  wooden  vessels  by 
pouring  over  them  hot  water  containing  a  part  of  the  sodium 
sulphide  required  for  the  dyeing.  The  dye-baths  should  be  of 
wood,  and  all  the  metallic  pipes  and  fittings  should  be  of  iron  or 
lead,  copper  and  brass  being  avoided  as  much  as  possible,  as 
these  have  a  bad  effect  on  the  dyes.  The  sodium  sulphide  in 
the  bath  should  be  sufficient  to  thoroughly  dissolve  all  the  dyestuff 
so  that  the  bath  is  clear;  if  the  bath  is  turbid,  more  sodium  sulphide 
should  be  added.  Unnecessary  boiling  of  the  dye-bath  should 
be  .avoided,  as  this  causes  the  oxidation  of  the  sulphide  to  too 
great  an  extent;  if  there  is  too  much  sodium  sulphide  present,  on 
the  other  hand,  the  cotton  will  not  take  up  the  color  well  and  the 
dyeings  will  appear  thin.  In  place  of  using  common-salt,  glauber- 
salt  may  be  used  with  like  effect.  In  order  to  control  the  amounts 


206  DYEING  AND    TEXTILE  CHEMISTRY. 

of  salts  which  are  present  in  standing  kettles  it  is  best  to  use 
hydrometer  tests;  for  blacks  the  cold  dye  liquor  should  stand  at 
8  to  10°  Tw.,  but  for  blues  and  other  colors  it  should  not  exceed 
4  to  5°  Tw.  It  should  be  borne  in  mind  that  10  parts  of  common- 
salt  are  equivalent  to  12  parts  of  calcined  glaubersalt  or  to  24  parts 
of  the  crystallized  glaubersalt.  In  special  cases  glucose,  dextrin 
and  Turkey-oil  red  are  added  to  the  bath  in  order  to  secure  better 
exhaustion  and  better  penetration  of  the  goods.  In  nearly  all 
cases  the  sulphur  dyes  may  be  dyed  in  a  boiling  bath,  though  just 
under  the  boil  is  a  better  practice;  in  the  case  of  some  blue  dyes, 
the  temperature  of  the  bath  should  not  be  over  85°  F.  The 
sulphur  colors  may  also  be  dyed  very  well  in  lukewarm  or  even 
cold  baths.  After  dyeing  it  is  important  that  the  goods  be  well 
squeezed  and  thoroughly  rinsed  immediately  after  coming  from 
the  dye-bath,  in  order  to  prevent  the  precipitation  of  unfixed 
dye-stuff  superficially  on  the  fibre;  this  gives  rise  to  more  even 
shades  and  the  colors  are  faster  to  rubbing.  With  some  of  the 
blues  it  is  necessary  to  oxidize  the  color  after  dyeing;  this  may 
be  done  by  squeezing  and  hanging  in  the  air,  or  by  steaming  in 
the  air. 

2.   List  of  the  Principal  Sulphur  Dyes. 

(d)  ORANGE. 

Eclipse  Orange.  Pyrogene  Orange 

Immedial  Orange.  Thiogene  Orange. 

(6)  YELLOW. 

Eclipse  Yellow.  Pyrogene  Yellow. 

Immedial  Yellow.  Thiogene  Golden  Yellow. 

Kryogene  Yellow.  Thiogene  Yellow. 

(c)  GREEN. 

Eclipse  Green.  Katigene  Olive. 

Eclipse  Olive.  Kryogene  Olive. 

Immedial  Green.  Nigrosulphine. 

Immedial  Olive.  Pyrogene  Olive. 

Katigene  Chrome  Blue  5G.  Pyrogene  Green. 

Katigene  Green.  Thiogene  Green. 


SULPHUR  DYES  ON  COTTON.  2O? 

(d)  BLUE. 

Eclipse  Blue.  Pyrogene  Blue. 

Immedial  Blue.  Pyrogene  Direct  Blue. 

Immedial  Direct  Blue.  Pyrogene  Indigo  Blue. 

Immedial  Indone.                      .  Sulphur  Blue. 

Immedial  Pure  Blue.  Thiogene  Blue. 

Immedial  Pure  Blue.  Thiogene  Cyanine. 

Immedial  Sky  Blue.  Thiogene  Dark  Blue. 

Katigene  Chrome  Blue.  Thiogene  Direct  Blue. 

Katigene  Indigo.  Thiogene  Violet. 

Kryogene  Blue.  Thion  Blue. 
Melanogene  Blue. 

(e)  BROWN. 

Cachou  de  Laval.  Pyrol  Brown. 

Eclipse  Bronze.  Sulphanil  Brown. 

Eclipse  Brown.  Sulphogene  Brown. 

Immedial  Bronze.  Sulphur  Brown. 

Immedial  Brown.  Thiocatechine. 

Immedial  Dark  Brown.  Thiogene  Brown. 

Katigene  Black  Brown.  Thiogene  Catechu. 

Katigene^Brown.  Thiogene  Dark  Red. 

Katigene  Chrome  Brown.  Thiogene  Khaki. 

Katigene  Yellow  Brown.  Thion  Brown. 

Kryogene  Brown.  Vulcan  Brown. 
Pyrogene  Brown. 

(/)  BLACK. 

Anthraquinone  Black.  Pyrol  Black. 

Auronal  Black.  Sulphanil  Black. 

Autogene  Black.  Sulphur  Black. 

Cross-Dye  Black  Sulphur  Blue  Black. 

Eclipse  Black.  Thiocarbone. 

Immedial  Black.  Thiogene  Black. 

Katigene  Black.  Thiogene  Black  Liquid. 

Katigene  Blue  Black.  Thiogene  Coal  Black. 

Kryogene  Black.  Thiogene  Diamond  Black. 

Melanogene.  Thion  Black. 

Mercaptol  Black.  Thional  Black. 

Pyrogene  Black.  Thiophenol  Black. 

Pyrogene  Gray.  Vidal  Black. 


208  DYEING   AND    TEXTILE   CHEMISTRY. 

SAMPLES. 

360.  Immedial  Brown  on  cotton;  general  method;  first  bath. 

361.  Immedial  Brown;  second  bath. 

362.  Immedial  Brown;  third  bath. 

363.  Immedial  Brown,  after-treated  with  chrome. 

364.  Washing  test  Immedial  Brown  before  chroming. 

365.  Washing  test  Immedial  Brown  after  chroming. 

366.  Cross-dye  test  Immedial  Brown  before  chroming. 

367.  Cross-dye  test  Immedial  Brown  after  chroming. 

368.  Sulphur  Black  A  extra  on  cotton. 

369.  Washing  test  Sulphur  Black  A  extra. 

370.  Cross-dye  test  Sulphur  Black  A  extra, 
37*.  Autogene  Black  on  cotton. 

372.  Washing  test  Autogene  Black. 

373.  Cross-dye  test  Autogene  Black. 

QUIZ  18. 

534-   Give  the  general  method  for  the  dyeing  of  sulphur  colors  on  cotton. 

535.  Does  the  dye-bath  with  sulphur  colors  exhaust  well?    How  may  this 
be  shown? 

536.  What  is  the  purpose  of  after-treating  sulphur  dyes  with  chrome  ?     How 
is  the  process  carried  out? 

537.  How  was  the  color  of  Immedial  Brown  affected  by  the  treatment  with 
chrome? 

538.  What  difference  was  noticed  in  the  fastness  of  the  untreated  and  the 
chromed  dyeings  with  Immedial  Brown  as  to  washing  and  cross-dyeing? 
How  were  these  tests  carried  out? 

539-   How  is  Sulphur  Black  A  extra  dyed  on  cotton  ?    What  character  of 
black  does  it  yield?    What  is  the  purpose  of  oiling  the  cotton  after  dyeing? 

540.  What  is  the  fastness  of  Sulphur  Black  A  extra  to  washing  and  cross- 
dyeing? 

541.  How  does  the  dyeing  of  Autogene  Black  differ  from  that  of  the  pre- 
vious color?    What  is  the  character  of  the  black  obtained?    What  is  its 
fastness  to  washing  and  cross-dyeing? 

542.  How  do  the  color  and  the  fastness  of  the  sulphur  blacks  compare 
with  those  of  the  developed  blacks? 

543-  To  what  general  group  do  the  sulphur  colors  belong?     What  was  the 
first  sulphur  dye  discovered  ?    How  was  it  prepared  ? 

544-  Have  the  sulphur  colors  been  in  general  use  for  any  length  of  time? 
Why  are  they  called  sulphur  colors? 

545'  Through  what  range  of  colors  do  the  sulphur  dyes  at  present  extend  ? 
546.   By  what  properties  are  the  sulphur  dyes  characterized? 


SULPHUR  DYES  ON  COTTON.  2OQ 

547.  What  substances  are  usually  added  to  the  dye-bath  in  using  sulphur 
dyes?     Give  the  function  of  each. 

548.  With  what  substances  may  the  sulphur  dyes  be  after-treated? 

549.  Do  all  sulphur  dyes  require  the  addition  of  sodium  sulphide  to  the 
bath? 

550.  About  what  amounts  of  dyestuff  are  required  for  the  production  of 
full  shades  in  dyeing  with  sulphur  colors? 

551.  How  should  the  sulphur  dyes  be  stored?    How  are  they  affected  by 
moist  air? 

552.  Why  is  such  a  large  amount  of  salt  used  in  dyeing  the  sulphur  colors? 
553-  What  is  the  best  manner  of  dissolving  the  sulphur  dyes?     Of  what 

should  the  dye-vats  consist,  and  what  metals  should  be  absent?    What  metals 
may  be  used  for  fittings? 

554.  How  should  the  amount  of  sodium  sulphide  in  the  bath  of  sulphur 
dyes  be  regulated  ?    What  does  turbidity  in  the  bath  indicate  ? 

555.  Why  should  excessive  boiling  of  the  dye-bath  be  avoided  when  using 
sulphur  colors? 

556.  If  too  much  sodium  sulphide  is  present  in  the  sulphur  color  bath  what 
defect  will  be  the  result? 

557.  In  the  sulphur  color  dye-bath  the  common-salt  may  be  replaced  by 
what  other  salt? 

558.  How  should  the  amounts  of  salts  present  in  standing  kettles  of  the 
sulphur  colors  be  regulated?    What  should  be  the  density  of  the  liquors  for 
blacks?    For  colors? 

559.  How  many  parts  of  calcined  glaubersalt  are  equivalent  to  100  parts 
of  common-salt?    What  is  the  proportion  between  calcined  glaubersalt  and 
crystallized  glaubersalt? 

560.  What  is  the  difference  as  to  composition  between  the  calcined  and  the 
crystallized  glaubersalts  ? 

561.  What  other  additions  are  sometimes  made  to  the  sulphur  color  dye- 
bath  besides  those  already  mentioned  in  order  to  obtain  better  exhaustion  and 
penetration  ? 

562.  At  what  temperature  is  it  best  to  dye  the  sulphur  colors?    Are  boiling 
baths  necessary? 

563.  Why  is  it  important  to  thoroughly  wash  the  goods  after  coming  from 
the  sulphur  dye-bath?    What  after-treatment  is  necessary  for  certain  blue 
sulphur  dyes,  and  how  is  this  after-treatment  conducted? 


SECTION  XIX. 

USE  OF  LOGWOOD  IN  DYEING. 

Experiment  112.  General  Method  of  Dyeing  Logwood  on 
Wool.  —  Mordant  four  test-skeins  of  woolen  yarn  in  the  usual 
manner  with  3  per  cent,  of  chrome  and  4  percent,  of  tartar;  wash 
well.  Dye  the  first  skein  in  a  bath  containing  2  per  cent,  of  log- 
wood extract  (solid) ;  enter  at  140°  F.,  gradually  raise  to  the 
boil,  and  dye  at  that  temperature  for  three-quarters  hour,  then 
wash  well  and  dry  (374).  Dye  the  second  skein  in  a  bath  con- 
taining 5  per  cent,  of  logwood  extract  in  the  same  manner  (375). 
Dye  the  third  skein  in  the  same  way  with  15  per  cent,  of  logwood 
extract  (376).  The  lower  percentages  of  logwood  give  bluish 
shades  on  a  chrome  mordant,  which  deepen  into  a  bluish  black  in 
the  heavy  percentage.  Dye  the  fourth  skein  in  a  bath  containing 
a  decoction  made  by  boiling  50  per  cent,  of  chipped  logwood  in 
300  cc.  of  water  (377).  Notice  that  at  first  the  dye-bath  is  of  a 
reddish  color,  but  that  the  black  develops  on  boiling. 

Experiment  113.  Effect  of  Over-Chroming.  —  Mordant  a  test- 
skein  of  woolen  yarn  with  10  per  cent,  of  chrome  and  4  per  cent, 
of  tartar  in  the  usual  manner;  wash  well,  and  dye  in  the  manner 
described  above  with  15  per  cent,  of  logwood  extract  (378).  It 
will  be  found  that  only  a  gray  color  is  produced;  this  is  the  result 
of  employing  too  much  chrome^  whereby  the  fibre  becomes 
oxidized  and  loses  its  affinity  for  the  dyestuff.  It  may  also  be 
probable  that  the  excess  of  chrome  has  some  injurious  action  on 
the  logwood  itself. 

Experiment  114.  Shading  Logwood  with  Alizarin  Yellow. — 
This  is  for  the  purpose  of  obtaining  a  deep  black  without  the 
bluish  tone  of  the  straight  logwood  black.  Mordant  a  skein  of 
woolen  yarn  in  the  usual  manner  with  3  per  cent,  of  chrome  and 
4  per  cent,  of  tartar;  wash,  and  dye  in  a  bath  containing  15  per 


USE  OF  LOGWOOD  IN  DYEING.  211 

cent,  of  logwood  extract  and  i  per  cent,  of  Alizarin  Yellow  AW. 
Enter  at  100°  F.,  gradually  raise  to  the  boil,  and  dye  at  that 
temperature  for  three-quarters  hour;  then  wash  well  and  dry 
(379)-  Compare  the  color  of  this  skein  with  that  dyed  with 
logwood  alone. 

Experiment  115.  Logwood  Black  on  Cotton  with  an  Iron 
Mordant.  —  The  principal  use  of  logwood  on  cotton  is  for  the 
production  of  blacks  and  grays  in  connection  with  an  iron  mor- 
dant. The  chief  salt  used  for  this  purpose  is  the  so-called 
"nitrate  of  iron."  The  mordant  is  fixed  by  means  of  tannin. 
Steep  a  test-skein  of  cotton  yarn  in  a  bath  containing  4  per  cent, 
of  tannic  acid;  enter  at  180°  F.,  work  for  15  minutes  at  that  tem- 
perature, then  allow  to  steep  under  the  liquor  without  further 
heating  for  i  hour.  Squeeze,  and  pass  through  a  bath  of  nitrate 
of  iron  at  4°  Tw.  for  15  minutes  cold;  then  squeeze  and  pass 
through  a  weak  bath  of  lime-water  cold  for  10  minutes,  and 
finally  wash  well  (380).  The  tannate  of  iron  thus  formed  on  the 
fibre  imparts  to  the  cotton  a  dark  gray  color.  Now  dye  the  skein 
in  a  bath  containing  15  per  cent,  of  logwood  extract  (solid)  and 
2  per  cent,  soda  ash;  entering  at  160°  F.,  gradually  raise  to  the 
boil,  and  dye  at  that  temperature  for  three-quarters  of  an  hour. 
Wash  well  and  dry  (381). 

Experiment  116.  To  Obtain  a  Faster  and  Clearer  Black. — 
Mordant  a  test-skein  of  cotton  yarn  in  the  same  manner  as  above 
with  4  per  cent,  of  tannic  acid,  and  then  fix  by  passing  through 
the  baths  of  nitrate  of  iron  and  lime-water.  Then  dye  as  before 
with  15  per  cent,  of  logwood  extract.  After  dyeing,  work  the 
skein  in  a  bath  containing  i  per  cent,  of  chrome;  enter  at  180°  F., 
work  for  15  minutes  at  that  temperature,  then  squeeze  and  wash 
well,  and  finally  soap  off  in  a  warm  dilute  soap  bath  (382). 
Instead  of  using  the  chrome  bath  the  dyed  material  may  be  passed 
back  into  the  nitrate  of  iron  bath.  This  after-treatment  and 
scouring  with  soap  have  the  effect  of  preventing  the  rusty 
appearance  liable  to  develop  when  logwood  is  dyed  with  an  iron 
mordant.  It  is  sometimes  the  practice  to  pass  the  cotton  through 
a  weak  lime  bath  after  coming  from  the  tannin  bath  and  before 


212  DYEING  AND   TEXTILE  CHEMISTRY. 

entering  the  bath  of  nitrate  of  iron;  this  causes  the  formation 
of  tannate  of  lime,  and  prevents  a  large  amount  of  the  unfixed 
tannin  from  passing  into  the  iron  bath  and  precipitating  tannate 
of  iron. 

Experiment  117.  Dyeing  Logwood  without  Tannin.  —  Cotton 
may  also  be  dyed  with  iron  and  logwood  without  the  intervention 
of  tannin.  Steep  a  test-skein  of  cotton  yarn  in  a  bath  containing 
nitrate  of  iron  at  8°  Tw.,  cold,  for  one-half  hour;  squeeze  and 
work  for  15  minutes  in  a  bath  containing  5  grams  of  soda  ash  at 
140°  F.  This  causes  a  precipitation  of  ferric  oxide  or  iron  buff 
in  the  fibre  (383).  Wash,  and  dye  as  previously  described  in 
experiment  i  with  15  per  cent,  of  logwood  extract  (384). 

Experiment  118.  Dyeing  Silk  a  Pure  Black  with  Logwood.  — 
By  "pure"  black  is  meant  one  which  does  not  contain  any 
weighting  materials.  Mordant  a  test-skein  of  silk  yarn  in  a  bath 
containing  150  cc.  of  water  and  20  per  cent,  of  cutch;  enter  at 
i2o°F.,  and  gradually  bring  to  the  boil,  then  allow  to  cool  in 
the  bath  for  one-half  hour;  next  rinse  the  skein  slightly  and  pass 
into  a  bath  of  nitrate  of  iron  at  10°  Tw.,  work  at  120°  F.  for  15 
minutes,  then  pass  through  a  dilute  bath  of  soda  ash,  and  wash 
well  (385).  Next  dye  in  a  bath  containing  150  cc.  of  water  and 
25  per  cent,  of  logwood  extract  (solid)  and  5  per  cent,  of  soda 
ash;  enter  at  140°  F.,  gradually  bring  to  the  boil,  and  dye  at  that 
temperature  for  one-half  hour,  then  wash  well  and  dry  (386). 

NOTES. 

i.  Logwood.  —  Logwood  is  obtained  from  the  Campeachy 
wood,  known  botanically  as  H&matoxylon  Campechianum;  it  is 
a  large  tree  and  grows  principally  in  tropical  and  sub-tropical 
America.  The  wood  itself  is  really  a  red-wood,  but  the  color- 
lake  as  finally  developed  is  black  or  blue,  depending  on  its  inten- 
sity. When  freshly  cut  the  wood  is  colorless  or  looks  about  like 
that  of  any  other  tree;  on  exposure  to  the  influence  of  the  oxygen 
of  the  air,  however,  the  outside  of  the  wood  becomes  of  a  dark 
reddish  brown  color,  due  to  the  development  of  the  coloring- 
matter.  The  coloring  principle  of  logwood  is  called  haematoxylin, 


USE  OF  LOGWOOD   IN  DYEING.  21$ 

and  this  on  oxidation  yields  hematin,  which  is  the  real  coloring- 
matter  of  the  prepared  logwood.  In  order  to  prepare  the  wood 
for  use  by  the  dyer,  the  logs,  after  having  the  outer  sapwood 
stripped  off,  are  either  rasped  or  chipped,  the  chips  being  placed 
in  large  heaps  and  moistened  with  water.  These  heaps  are  turned 
over  from  time  to  time  to  allow  the  oxygen  of  the  air  free  access  to 
the  wood.  Fermentation  occurs,  which  results  in  the  formation  of 
the  hematin.  The  dyewood  in  this  state  may  now  be  used  by  the 
dyer,  but  at  the  present  time  it  is  customary  to  carry  the  manu- 
facture of  the  dyestuff  still  further  and  prepare  an  extract  either 
in  the  solid  or  the  liquid  form. 

Logwood  is  about  the  only  natural  coloring-matter  which  is  still 
extensively  used  (with  the  exception  of  indigo).  Its  principal 
use  at  the  present  time  is  for  the  black  dyeing  of  silk  and  leather; 
its  use  on  cotton  is  decreasing,  and  on  wool  it  is  used  only  for  very 
cheap  blacks.  This  is  due  to  the  fact  that  there  are  several 
blacks  for  both  wool  and  cotton  which  are  much  faster  than 
logwood.  On  wool  logwood  is  almost  entirely  used  on  a  chrome 
mordant,  and  the  color  obtained  is  a  bluish-black.  About  15  per 
cent,  of  logwood  extract  is  required  for  the  production  of  full 
shades.  To  neutralize  the  bluish  tone  of  the  straight  logwood,  it 
was  formerly  the  custom  to  use  some  fustic  (a  yellow  wood  color) 
in  connection  with  the  logwood.  Fustic  is  still  used  in  this 
manner,  but  as  it  is  rather  fugitive,  it  is  better  to  employ  a  faster 
mordant  yellow  dyestuff  for  this  purpose.  In  the  dyeing  of  log- 
wood it  is  to  be  noticed  that  an  excess  of  chrome  in  the  mordant- 
ing bath  is  injurious  to  the  color.  Sometimes  logwood  black  on 
wool  is  after-chromed  for  the  purpose  of  making  the  color  faster 
to  washing  and  fulling.  Stannous  chloride  is  at  times  added  to 
the  dye-bath  for  the  purpose  of  giving  a  violet  tone  to  the  black. 
Logwood  extract  is  sometimes  -mixed  with  copperas  and  blue- 
stone  and  sold  in  the  form  of  a  paste  as  a  direct  logwood  black 
for  wool;  it  is  dissolved  by  adding  oxalic  acid  to  the  bath.  A 
direct  chrome  black  can  also  be  prepared  by  precipitating  a 
solution  of  logwood  with  chrome  and  dissolving  the  precipitate 
in  oxalic  acid.  Sometimes  wool  is  first  dyed  in  the  indigo  vat  to 


214  DYEING   AND    TEXTILE   CHEMISTRY. 

a  blue,  and  then  topped  off  with  logwood,  giving  a  bluish  black; 
this  is  known  as  a  "woaded"  black. 

Logwood  is  chiefly  dyed  on  cotton  in  connection  with  an  iron 
mordant,  "nitrate  of  iron"  being  principally  used.  The  iron 
salt  is  generally  fixed  on  the  cotton  by  tannin  preliminary  to 
dyeing,  but  at  times  .the  fixation  of  the  iron  is  accomplished  by 
the  tannin  naturally  present  in  the  logwood  extract.  As  the  iron 
mordant  gives  a  brownish  or  rusty  black,  it  is  advisable  to  chrome 
the  color  obtained  to  produce  a  clearer  and  more  desirable  black. 
The  development  of  the  rusty  appearance  on  an  iron-logwood 
black  on  cotton  may  also  be  prevented  more  or  less  by  soaping 
the  dyed  color.  By  the  addition  of  bluestone  to  the  dye-bath  the 
color  is  also  said  to  be  improved  in  appearance. 

Logwood  is  still  used  extensively  for  the  black  dyeing  of  silk, 
both  unweighted  and  weighted.  It  is  used  in  connection  with  a 
tannin-iron  mordant,  the  tannin  employed  usually  being  cutch. 
Logwood  seems  to  make  the  silk  fibre  opaque,  which  is  a  necessary 
condition  for  the  production  of  a  full  deep  black;  the  coal-tar 
blacks,  as  a  rule,  do  not  make  the  silk  sufficiently  opaque. 

2.  General  Use  of  Natural  Dyes.  —  Previous  to  the  discovery 
of  the  coal-tar  dyes  the  textile  colorist  had  to  rely  upon  either  the 
mineral  pigments  or  the  dyestuffs  derived  from  the  various 
vegetable  substances  for  the  production  of  his  effects.  The 
vegetable  dyes  nearly  all  belong  to  the  mordant  class  of  dyestuffs, 
though  a  few  such  as  turmeric,  safflower,  and  annatto  exhibit 
substantive  properties  to  a  certain  degree,  and  may  be  dyed 
directly  on  cotton.  In  general,  however,  in  using  the  natural 
dyewoods  on  either  wool  or  cotton  it  is  first  necessary  to  mordant 
the  material  in  the  usual  manner  with  metallic  salts. 

The  coloring-matters  present  in  the  dyewoods  were  usually 
extracted  by  the  dyer  himself  by  simply  boiling  the  rasped  wood 
in  water  and  using  this  solution  as  a  dye-bath.  Under  these 
conditions,  however,  the  coloring-matter  so  obtained  was  never 
in  a  pure  condition,  but  was  contaminated  with  more  or  less 
resinous  and  tannin  matter  which  acted  frequently  in  a  delete- 
rious manner  in  the  dyeing.  The  first  application  of  chemical 


USE  OF  LOGWOOD    IN  DYEING.  21$ 

science  to  the  art  of  dyeing  was  the  attempt  to  manufacture 
purer  and  more  homogeneous  dye  products  from  the  extracts  of 
the  various  dyewoods  or  other  vegetable  coloring-matters.  At 
the  present  time  the  use  of  the  natural  dyewoods  has  almost 
disappeared  with  the  exception  of  logwood,  fustic,  and  indigo; 
and  even  the  latter  is  now  a  coal-tar  product  which  is  rapidly 
driving  the  natural  article  from  the  market.  Logwood  still 
holds  its  own  for  the  production  of  cheap  blacks  on  wool  and 
cotton,  and  it  is  also  largely  used  in  the  black  dyeing  of  silk. 
Fustic  is  used  to  some  extent  in  connection  with  the  foregoing 
to  tone  the  shade  of  the  black  obtained,  but  even  its  use  in 
this  manner  is  growing  less  and  less,  being  replaced  by  other 
yellow  coloring-matters  which  possess  a  greater  degree  of  fast- 
ness. Cutch  is  still  used  for  the  production  of  brown  shades 
on  cotton,  but  it  is  more  used  as  a  tannin  mordant  than  as  a 
self  color. 

The  natural  dyewoods  yield  coloring-matters  from  which  may 
be  dyed  black,  red,  brown,  yellow,  blue,  violet,  etc.;  there  is, 
however,  no  good  green  dye  among  the  list  of  natural  dyestuffs. 
The  colors  obtained  with  the  natural  dyes,  as  a  rule,  are  rather 
dull  in  appearance,  and  many  of  them  are  of  questionable  fast- 
ness, there  being  many  of  the  mordant  coal-tar  dyes  which  are 
far  superior  in  this  respect. 

SAMPLES. 

374.  Wool  dyed  with  2  per  cent,  logwood  on  chrome  mordant. 

375.  Dyeing  with  5  per  cent,  logwood. 

376.  Dyeing  with  15  per  cent,  logwood. 

377.  Dyeing  with  50  per  cent,  logwood  chips. 

378.  Showing  effect  of  over-chroming. 

379.  Logwood  shaded  with  Alizarin  Yellow. 

380.  Cotton  mordanted  with  tannin-iron  for  logwood. 

381.  Cotton  dyed  with  logwood  on  iron  mordant. 

382.  Logwood  on  cotton  after-chromed. 

383.  Cotton  mordanted  with  iron  oxide  for  logwood. 

384.  Cotton  dyed  with  logwood  without  tannin  mordant. 

385.  Silk  mordanted  with  cutch  and  iron  for  logwood. 

386.  Silk  dyed  with  logwood  on  tannin-iron  mordant. 


2l6  DYEING   AND    TEXTILE   CHEMISTRY. 


QUIZ  19. 

564.  What  is  the  general  method  for  the  dyeing  of  logwood  on  wool? 

565.  What  mordant  is  principally  used  in  the  dyeing  of  logwood  on  wool? 

566.  What  color  do  small  percentages  of  logwood  give  on  a  chrome  mor- 
dant ?    What  color  do  heavy  percentages  give  ? 

567.  How  much  solid  logwood  extract  would  be  required  to  dye  a  black  on 
100  Ibs.  of  wool? 

568.  In  dyeing  with  logwood  chips  how  is  the  bath  prepared?    What 
amount  of  logwood  is  required  to  give  a  black  when  used  in  this  form  ? 

569.  What  is  the  color  of  the  solution  of  logwood?    Describe  the  changes 
in  color  of  the  wool  as  the  dyeing  proceeds. 

570.  What  is  the  effect  on  the  logwood  black  when  too  much  chrome  is  used 
as  the  mordant?    To  what  causes  may  this  be  due?    What  is  the  proper 
amount  of  chrome  to  use  ? 

571 .  What  tone  of  black  does  a  straight  logwood  give  on  a  chrome  mordant  ? 
How  may  such  a  black  be  shaded  in  order  to  produce  a  dead  black  ? 

572.  Explain  why  the  addition  of  a  small  amount  of  yellow  dyestuff  to  the 
logwood  bath  produces  a  fuller  shade  of  black.     What  dyes  may  be  used  for 
this  purpose  ? 

573-   What  is  the  general  method  for  the  dyeing  of  logwood  black  on  cotton  ? 

574.  What  is  the  chief  salt  of  iron  employed  for  mordanting  cotton  for  log- 
wood black  ? 

575-  Of  what  does  the  so-called  "nitrate  of  iron"  consist?  Why  is  it  given 
this  name  ? 

576.  How  is  the  iron  mordant  fixed  on  the  cotton  when  using  "nitrate  of 
iron  "  ?     What  is  the  color  of  the  mordanted  cotton  ? 

577.  What  is  the  purpose  of  treating  the  mordanted  cotton  with  a  bath  of 
lime-water?    What  salt  of  iron  is  formed  in  the  fibre  when  mordanting  with 
iron  and  tannin  ? 

578.  How  is  the  dye-bath  prepared  for  dyeing  cotton  black  with  logwood 
on  an  iron  mordant  ?     How  much  logwood  extract  is  required  to  give  a  black  ? 

579.  How  may  the  rusty  appearance  of  the  logwood-iron  black  on  cotton 
be  prevented?     Give  the  reasons  for  the  processes  employed. 

580.  What  is  the  purpose  of  passing  the  tanned  cotton  through  lime-water 
before  mordanting  with  iron  liquor?     Explain  the  reaction  which  takes  place. 

581 .  How  may  an  iron-logwood  black  be  dyed  on  cotton  without  the  use  of 
a  preliminary  tannin  bath  ?     How  is  the  iron  mordant  fixed,  and  what  is  the 
color  of  the  mordanted  cotton  ? 

582 .  Give  the  general  method  for  the  dyeing  of  silk  with  logwood. 

583-  What  is  meant  by  a  "pure"  black  on  silk?     By  a  "weighted"  black? 
584.  What  is  the  mordant  employed  in  dyeing  silk  with  logwood?    What 
tannin  is  generally  used  for  fixing? 


USE  OF  LOGWOOD   IN  DYEING.  21  f 

585.  Of  what  does  the  dye-bath  consist  when  dyeing  logwood  black  on  silk  ? 
What  is  the  color  of  the  mordanted  silk  before  dyeing  ? 

586.  Why  is  logwood  so  called,  and  from  what  is  it  obtained?    What  is  its 
botanical  name  ?    Where  does  logwood  grow  ? 

587.  To  what  class  of  dyewoods  does  logwood  really  belong  ?    What  is  the 
nature  of  the  color-lake  formed  with  metallic  mordants  ? 

588.  What  is  the  color  of  logwood  when  freshly  cut  ?    What  change  occurs 
when  exposed  to  the  air? 

589.  What  is  the  coloring  principle  of  logwood?    What  does  this  yield  on 
oxidation  ? 

590.  How  is  logwood  prepared  for  use  in  dyeing  ?    Are  logwood  chips  much 
used  at  present  by  the  dyer  ? 

591 .  What  position  does  logwood  hold  among  the  natural  dyestuffs  ?    What 
is  its  principal  use  at  the  present  time  ? 

592.  Why  has  the  use  of  logwood  for  the  dyeing  of  wool  and  cotton  dimin- 
ished of  late  years  ? 

593-  What  is  the  use  of  fustic  in  connection  with  logwood  dyeing?    Why 
is  fustic  not  used  so  much  at  present  ? 

594.  What  is  the  purpose  of  after-chroming  logwood  black  on  wool  ?    What 
is  the  effect  of  using  tin  salts  in  the  dye-bath  with  logwood  ? 

595.  Of  what  does  the  "direct  logwood  black  for  wool"  consist?    How  is 
it  dyed? 

596.  How  may  a  direct  chrome  logwood  black  for  wool  be  prepared? 
What  is  meant  by  a  "woaded"  black  on  wool? 

597.  What  is  the  defect  of  the  iron-logwood  black  dyed  on  cotton?     How 
may  this  be  overcome  ? 

598.  What  is  the  effect  of  adding  bluestone  to  the  dye-bath  of  logwood  on 
cotton  ? 

599.  In  what  manner  does  logwood  black  on  silk  differ  from  the  general 
run  of  coal-tar  blacks? 


SECTION  XX. 
THE  MINOR  NATURAL  DYES. 

Experiment  119.  Use  of  Fustic.  —  Mordant  a  test-skein  of 
woolen  yarn  with  3  per  cent,  of  chrome  and  4  per  cent,  of  tartar 
in  the  usual  manner.  Dye  for  45  minutes  in  a  bath  containing 
10  per  cent,  of  fustic  extract,  entering  at  140°  F.  and  gradually 
raising  to  the  boil.  Wash  well  and  dry  (387).  Mordant  a  second 
skein  with  5  per  cent,  of  stannous  chloride  and  5  per  cent,  of 
oxalic  acid,  and  dye  in  the  same  manner  as  above  with  10  per 
cent,  of  fustic  extract  (388).  Mordant  a  third  skein  with  6  per 
cent,  of  ferrous  sulphate  and  8  per  cent,  of  tartar,  and  dye  as  before 
with  10  per  cent,  of  fustic  extract  (389).  Note  the  difference  in 
color  obtained  from  the  fustic  by  the  use  of  different  mordants. 
Test  the  fastness  of  the  color  to  washing  and  light,  and  compare 
the  results  with  those  given  by  Alizarin  Yellow. 

Experiment  120.  Use  of  Madder.  —  This  dyestuff  was  formerly 
very  extensively  employed,  but  has  now  been  replaced  almost 
entirely  by  the  synthetically  prepared  Alizarin  which  is  the 
coloring  principle  of  madder.  Madder  consists  of  the  ground 
root  of  Rubia  tinctorum,  and  is  applied  as  a  mordant  dyestuff. 
Mordant  a  test-skein  of  woolen  yarn  with  3  per  cent,  of  chrome 
and  4  per  cent,  of  tartar,  and  dye  for  45  minutes  in  a  bath  prepared 
by  boiling  25  per  cent,  of  madder  in  water  and  straining.  Also 
add  4  per  cent,  of  calcium  acetate  to  the  dye-bath.  This  mordant 
yields  a  reddish  brown  color  with  madder  (390).  In  a  similar 
manner  dye  a  test-skein  which  has  been  mordanted  with  10  per 
cent,  of  aluminium  sulphate  and  8  per  cent,  of  tartar  (391)-  This 
mordant  yields  a  dull  red  color.  Dye  a  third  test-skein  mor- 
danted with  5  per  cent,  of  stannous  chloride  and  5  per  cent,  of 
oxalic  acid,  and  notice  that  an  orange-red  color  is  obtained 
(392). 

218 


THE  MINOR  NATURAL  DYES.  219 

Experiment  121.  Use  of  Archil.  —  This  dye,  together  with 
the  related  coloring-matter  cudbear,  is  but  little  used  at  present. 
It  possesses  the  character  of  a  substantive  dye  towards  wool  and 
yields  a  dull  magenta  shade.  It  can  be  applied  in  a  neutral  bath, 
though  the  addition  of  acid  makes  the  color  redder  and  brighter. 
The  color  is  not  fast  to  light  or  fulling,  and  only  fairly  so  to 
washing.  Dye  a  test-skein  of  woolen  yarn  in  a  neutral  bath 
containing  20  per  cent,  of  archil  paste,  entering  at  i2o°F.  and 
raising  to  the  boil  for  45  minutes  (393).  Dye  a  second  skein  in 
a  bath  containing  20  per  cent,  of  archil  paste  and  4  per  cent,  of 
sulphuric  acid  (394).  Notice  the  difference  in  the  color  caused 
by  the  use  of  the  acid  in  the  dye-bath.  Archil  at  the  present 
time  is  not  used  as  a  self  color,  but  in  combination  with  various 
acid  dyes  for  the  production  of  browns,  maroons,  and  clarets; 
it  is  also  employed  as  a  bottom  for  indigo.  It  is  not  used  for 
the  dyeing  of  cotton.  Silk  may  be  dyed  with  archil  in  a  soap 
bath,  with  or  without  the  addition  of  acetic  acid. 

Experiment  122.  Use  of  Quercitron.  —  This  is  a  yellow  color- 
ing-matter obtained  from  the  bark  of  a  species  of  oak.  Quer- 
citron itself  consists  of  the  ground  bark,  while  flavine  is  the  pure 
dry  extract  of  the  coloring-matter.  Mordant  a  test-skein  of 
woolen  yarn  with  3  per  cent,  of  chrome  and  4  per  cent,  of  tartar 
in  the  usual  manner,  and  then  dye  with  10  per  cent,  of  quercitron 
bark,  boiling  for  45  minutes  (395).  On  this  mordant  quercitron 
gives  an  olive-yellow  color.  Mordant  another  test-skein  with 
4  per  cent,  of  stannous  chloride  and  2  per  cent,  of  oxalic  acid; 
remove  the  skein  from  the  mordanting  bath,  add  i  per  cent,  of 
flavine  extract,  boil  up  for  5  minutes,  then  reenter  the  wool  and 
continue  boiling  for  45  minutes  (396).  This  method  of  dyeing 
should  yield  a  bright  canary-yellow.  By  increasing  the  amount  of 
flavine  the  color  becomes  orange-yellow.  Quercitron  and  its  pro- 
ducts are  but  little  used  for  wool  dyeing  at  present,  though  they 
are  still  employed  to  some  extent  in  both  cotton  and  wool  printing. 
The  color  is  not  particularly  fast  to  either  light  or  scouring. 

Experiment  123.  Use  of  Cutch.  —  This  brown  dyestuff  is  also 
a  tannin,  and  in  this  latter  connection  it  has  already  been  con- 


220  DYEING  AND    TEXTILE  CHEMISTRY. 

sidered  (see  page  127).  As  a  dyestuff  it  was  formerly  very  exten- 
sively used  on  cotton,  and  for  the  production  of  certain  tones  of 
brown  it  is  still  employed  quite  largely  in  cotton  dyeing.  It  is 
not  used  for  the  dyeing  of  wool,  as  the  fibre  is  made  too  harsh. 
In  silk  dyeing  it  is  largely  used,  but  only  as  a  tannin  in  connection 
with  logwood  black.  Prepare  a  bath  containing  1 5  per  cent,  of 
cutch  and  dye  a  test-skein  of  cotton  yarn  for  i  hour  at  195°  to 
210°  F.  Then  squeeze  the  skein  and  treat  for  30  minutes  at 
1 60°  F.  in  a  bath  containing  5  per  cent,  of  chrome,  and  finally 
give  a  thorough  washing  (397).  Darker  shades  of  brown  are 
obtained  by  the  addition  of  bluestone  to  the  dye-bath  as  follows : 
Dye  a  test-skein  of  cotton  yarn  in  a  bath  containing  15  per  cent,  of 
cutch  and  2  per  cent,  of  bluestone;  squeeze  and  treat  with  chrome 
solution  as  above  (398). 

Experiment  124.  Use  of  Cochineal.  —  This  dyestuff  consists 
of  the  dried  bodies  of  small  insects  and  furnishes  a  bright  red 
coloring-matter.  Before  the  introduction  of  the  red  acid  dyes 
it  was  largely  used  for  the  production  of  bright  scarlet  colors  on 
wool,  and  it  still  has  a  certain  degree  of  use  for  this  purpose. 
Mordant  a  test-skein  of  woolen  yarn  with  6  per  cent,  of  stannous 
chloride  and  4  per  cent,  of  oxalic  acid ;  wash,  and  dye  in  a  fresh 
bath  containing  10  per  cent,  of  ground  cochineal,  starting  at  a 
temperature  of  140°  F.  and  raising  to  the  boil  for  45  minutes 
(399).  When  dyed  on  a  tin  mordant  in  this  manner  a  bright 
scarlet  color  is  obtained  which  is  fast  to  light  and  fulling.  A 
crimson-red  color  is  obtained  with  an  aluminium  mordant  as 
follows :  Mordant  a  test-skein  of  woolen  yarn  with  8  per  cent,  of 
aluminium  sulphate  and  6  per  cent,  of  tartar;  wash,  and  dye  in 
a  fresh  bath  containing  10  per  cent,  of  ground  cochineal  (400). 
Cochineal  is  not  used  for  the  dyeing  of  cotton. 

NOTES. 

i.  Fustic.  —  This  coloring-matter  is  obtained  from  the  wood 
of  a  tree  botanically  known  as  Moms  tinctoria.  It  is  also  known 
as  Cuba  wood  or  yellow  wood.  It  is  obtained  in  the  West  Indies 
and  Central  and  South  America,  the  best  varieties  being  obtained 


THE  MINOR  NATURAL  DYES.  221 

from  Cuba  and  Tampico.  Fustic  gives  a  bright  yellow  color 
with  an  alum  mordant,  with  chromium  an  olive-yellow,  with  iron 
a  dark  olive,  with  copper  an  olive,  and  with  tin  a  bright  orange- 
yellow.  Fustic  may  be  used  either  in  the  form  of  the  chipped 
wood  or  as  the  extract,  the  latter  being  obtainable  either  as  paste 
or  solid.  At  present  it  is  seldom  used  as  a  self  color,  but  it  still 
finds  considerable  use  in  connection  with  logwood  for  the  dyeing 
of  dead-black  shades. 

Fustic  appears  to  contain  two  coloring-matters,  morintannic 
acid  and  morin.  The  former,  known  also  as  maclurin,  is  readily 
soluble  in  water,  and  may  be  crystallized  from  solution  in  the 
form  of  light  yellow  microscopic  needles.  It  has  the  composition 
C13H10O6;  when  heated  with  strong  caustic  alkali  it  is  decom- 
posed into  phloroglucin  and  protocatechuic  acid.  It  dissolves  in 
cold  concentrated  sulphuric  acid  with  a  yellow  color  and  is  repre- 
cipitated  on  dilution  with  water.  If  the  strong  acid  solution  is 
allowed  to  stand  for  some  days  it  deposits  brick-red  crystals  of 
rufimoric  acid.  If  a  solution  of  morintannic  acid  is  treated  with 
zinc  and  sulphuric  acid,  the  solution  becomes  red  and  then 
orange,  and  contains  phloroglucin  and  machromin;  the  latter 
crystallizes  in  slender  needles  which  become  blue  on  exposure  to 
the  air.  Hydrochloric  acid  gives  a  blue  precipitate,  and  the 
alkaline  solution  also  becomes  blue  on  exposure  to  the  air.  A 
solution  of  machromin  with  ferric  chloride  gives  a  violet  color 
gradually  becoming  blue;  mercuric  chloride  gives  the  same  result. 
A  solution  of  morintannic  acid  with  gelatin  gives  a  yellow  pre- 
cipitate, with  ferro-ferric  sulphate  a  greenish  precipitate,  acetate 
of  lead  a  yellow  precipitate,  and  stannous  chloride  an  orange 
precipitate.  Morin,  on  the  other  hand,  is  almost  insoluble  in 
cold  water,  and  only  slightly  soluble  in  boiling  water.  It  is  also 
known  as  moric  acid,  and  has  the  formula  C12H10O6.  It  is  soluble 
in  alkalies,  with  a  yellow  color,  from  which  solution  it  is  reprecipi- 
tated  by  the  addition  of  acids.  It  is  soluble  in  alcohol,  and  this 
solution  with  ferric  chloride  gives  an  olive-green  color.  Morin 
appears  to  give  much  deeper  shades  with  chromium  and  alumin- 
ium mordants  than  morintannic  acid,  but  it  gives  lighter  shades 


222  DYEING   AND    TEXTILE   CHEMISTRY. 

with  iron  mordants.  Morintannic  acid  may  be  prepared  from 
commercial  fustic  extract  by  allowing  the  concentrated  syrupy 
solution  to  stand  for  some  days,  when  an  abundant  crystalline 
deposit  will  be  formed;  this  is  washed  rapidly  with  a  little  cold 
water  and  strongly  pressed.  The  resulting  mass  is  boiled  twice 
with  water,  whereon  a  solution  containing  morintannic  acid  will 
be  obtained,  the  residue  consisting  of  moric  acid  and  morate  of 
lime.  The  aqueous  solution  is  concentrated  by  evaporation, 
and  precipitated  by  the  addition  of  hydrochloric  acid.  Pure 
moric  acid  may  be  obtained  from  the  residue  by  treating  with 
dilute  hydrochloric  acid  (to  decompose  the  calcium  morate)  and 
dissolving  in  alcohol.  On  diluting  with  water  this  solution 
deposits  moric  acid  in  the  form  'of  yellow  needles. 
A  solution  of  fustic  gives  the  following  reactions: 

Alkalies:  Orange  to  brown  color. 

Weak  acids:  Pale  yellow  precipitate. 

Alum:  Bright  yellow  precipitate. 

Lead  acetate:  Orange  precipitate. 

Copper  acetate:  Brownish  yellow  precipitate. 

Ferrous  sulphate:  \  At   first   olive  color,  then   brownish  olive 

Ferric  sulphate:     }      precipitate  on  standing. 

Stannous  chloride:  Brownish  yellow  precipitate. 

Copper  sulphate:  Dark  green  precipitate. 

Gelatin:  Yellow  flocculent  precipitate. 

Fustic  occurs  in  commerce  in  the  form  of  log,  chipped,  rasped, 
ground,  or  as  an  extract.  The  extract  is  frequently  sophisticated 
with  glucose  and  quercitron  bark  extract,  and  varies  in  its  spe- 
cific gravity  from  40°  to  51°  Tw.  The  specific  gravity,  however, 
like  that  of  logwood,  is  of  no  guide  to  its  value,  on  account  of 
its  being  increased  by  the  addition  of  adulterants.  The  best 
method  of  making  a  valuation  of  fustic  in  any  of  its  forms  is 
to  conduct  a  series  of  comparative  dye-tests  on  skeins  of 
woolen  yarn  which  have  been  previously  mordanted  with  3 
per  cent,  of  chrome  and  4  per  cent,  of  tartar,  as  in  the  case  of 
logwood,  or  with  3  per  cent,  of  stannous  chloride  and  5  per 


THE  MINOR  NATURAL  DYES.  22$ 

cent,  of  oxalic  acid.  The  tests  are  carried  out  in  the  usual 
manner. 

Fustic  is  more  used  on  wool  than  on  cotton,  and  the  general 
mordant  employed  is  chrome,  though  when  bright  yellow  colors 
are  desired  aluminium  or  tin  mordants  are  used.  The  color 
obtained  with  the  latter,  however,  is  not  very  fast  to  washing  and 
is  quite  fugitive  to  light,  becoming  duller  and  browner  on  expo- 
sure. Even  on  a  chrome  mordant,  however,  the  color  cannot  be 
classified  as  fast  to  light.  In  the  dyeing  of  fustic  prolonged 
boiling  must  be  avoided,  as  this  causes  the  color  to  be  dull  and 
brownish,  probably  due  to  the  presence  of  considerable  tannin 
matter  in  the  dyestuff  which  by  protracted  boiling  and  oxidation 
suffers  decomposition  into  brownish  coloring-matters.  The 
addition  of  some  glue  solution  to  the  dye-bath  is  said  to  obviate 
this  defect. 

Another  coloring-matter  similar  to  fustic,  and  which  once  had 
considerable  use,  is  the  so-called  young  fustic.  This  dyestuff 
consists  of  the  ground  wood  of  the  sumac  tree,  Rhus  cotinus.  It 
was  employed  in  practically  the  same  manner  as  fustic  (which 
was  known  as  old  fustic),  but  was  a  much  inferior  dyestuff,  owing 
to  its  fugitive  character.  It  has  now  practically  disappeared 
from  trade. 

2.  Madder.  —  This  dyestuff  was  formerly  of  very  great  impor- 
tance, and  was  largely  cultivated  in  the  southern  part  of  Europe 
and  Asia  Minor.  It  was  used  for  the  production  of  Turkey-red 
on  cotton  and  the  dyeing  of  red  on -wool.  Madder,  however,  has 
long  been  replaced  by  the  coal-tar  alizarin,  which  is  identical  in 
composition  and  properties  to  the  natural  product. 

Madder  is  the  ground  root  of  the  plant  known  as  Rubia  tinct- 
orum;  the  principal  coloring-matters  yielded  by  the  madder  root 
are  alizarin,  purpurin,  pseudo-purpurin,  xanthin,  and  chlorogenin; 
the  aqueous  extract  also  contains JFrom  loto  15  percent,  of  sugar. 
The  most  important  of  these  constituents  is  the  alizarin;  the 
other  coloring-matters,  especially  the  xanthin  and  chlorogenin, 
have  a  deleterious  effect  in  dulling  the  color  produced  by  the 
alizarin.  The  coloring-matters  exist  in  the  root  in  the  form  of 


224  DYEING  AND    TEXTILE   CHEMISTRY. 

glucosides,  which  are  split  up  into  the  dyestuffs  and  a  sugar 
through  the  action,  of  a  particular  ferment. 

Alizarin,  which  is  the  principal  coloring- matter  of  the  madder, 
may  be  obtained  therefrom  by  extracting  the  ground  root  with 
alcohol,  evaporating  the  solution  to  dryness,  powdering  the 
residue,  spreading  it  on  a  filter  paper  on  a  heated  plate;  the 
extract  melts  and  the  paper  absorbs  the  brown  resinous  matters, 
while  the  alizarin  sublimes  on  the  surface  of  the  mass  as  large 
orange-red  crystals. 

Alizarin  possesses  the  characteristics  of  a  phenol,  and  is  readily 
soluble  in  alkalies,  with  red  color;  it  is  only  slightly  soluble  in 
boiling  water,  with  a  yellow  color.  Its  solution  gives  the  follow- 
ing reactions: 

Alkalies:  Bluish  claret  color. 

Acids:  Brownish  yellow  color. 

Alum:  Brownish  red  precipitate. 

Stannous  chloride:  Brownish  red  precipitate. 

Iron  salts:  Dark  brown  precipitate. 

Copper  salts:  Reddish  brown  precipitate. 

Barium  and  calcium  chlorides:  Violet  precipitates. 

Lead  acetate:  Reddish  violet  precipitate. 

When  alizarin  is  distilled  with  zinc  it  gives  anthracene,  from 
which  reaction  its  synthetic  preparation  from  the  latter  body  was 
finally  discovered. 

Purpurin,  which  also  exists  in  the  madder  root,  resembles 
alizarin,  but  is  more  yellow  in  color.  It  may  be  prepared  from 
alizarin  by  heating  the  latter  with  manganese  dioxide  and 
sulphuric  acid. 

Madder  was  used  principally  in  the  form  of  the  ground  root, 
but  there  were  also  numerous  extracts  and  preparations  made 
for  the  use  of  the  dyer.  Garancin  was  obtained  by  treating  the 
wet  paste  of  madder  with  concentrated  sulphuric  acid;  100  parts 
of  madder  gave  from  30  to  40  parts  of  garancin,  but  this  possessed 
four  to  five  times  the  dyeing  power  of  the  original  madder.  It  is 
supposed  that  other  bodies  which  detracted  from  the  good  color 


THE  MINOR  NATURAL  DYES.  22$ 

of  the  alizarin  in  the  madder  were  removed  by  this  treatment,  and 
also  any  coloring-matter  which  may  have  been  combined  as 
metallic  salts  was  liberated  and  rendered  more  active  in  dyeing. 
Garanceux  was  obtained  from  spent  madder  by  the  same  process 
as  the  above;  its  coloring  power,  however,  was  only  about  one- 
third  that  of  good  garancin.  Fleurs  de  garance,  or  flowers  of  mad- 
der, was  prepared  by  treating  madder  with  dilute  sulphuric  acid, 
whereby  any  yellow  coloring-matters  were  removed.  To  prepare 
it,  mix  100  parts  of  madder  with  i  part  sulphuric  acid  and  1000 
parts  water,  and  allow  the  mixture  to  macerate  for  10  hours;  filter, 
wash  the  paste,  press  and  dry.  The  acid  liquors  from  this  process 
were  used  for  the  manufacture  of  alcohol,  as  they  contained  con- 
siderable sugar;  100  parts  madder  yielded  about  10  parts  alcohol. 
Madder  gives  the  following  colors  with  the  different  mordants: 

Chromium:  Bluish  red  to  crimson. 
Aluminium:  Pink  to  scarlet. 
Iron:  Maroon  to  reddish  brown. 
Copper:  Yellowish  brown. 
Tin:  Reddish  orange. 

Madder  is  still  used  in  the  woad  indigo  vat,  but  in  this  case  it  is 
more  employed  for  its  fermenting  properties  than  for  any  coloring 
power. 

The  chief  varieties  of  madder  are  Dutch,  Alsatian,  Avignon, 
and  Turkish.  Dutch  madder  is  coarsely  ground,  and  if  kept  in 
a  moist  place  tends  to  cake  together.  Crop  madder,  which  is  the 
ground  inner  portion  of  the  root,  is  considered  as  the  best  quality, 
while  the  outer  part  is  known  as  mulle  madder,  and  is  the  poorest. 
Alsatian  madder  is  very  like  the  Dutch.  Avignon  madder  is 
known  in  two  varieties,  the  palus  and  the  rosee.  The  former 
is  much  the  darker  in  appearance,  due  to  the  nature  of  the  soil 
on  which  it  is  grown.  Avignon  madder  does  not  require  to  be 
matured  by  storage  for  as  long  a  time  as  Dutch  and  Alsatian 
madders,  which  should  be  stored  in  casks  for  two  years  before 
use.  Turkish  madder  is  exported  chiefly  from  Smyrna  and  is 
very  rich  in  coloring-matter. 


226  DYEING   AND    TEXTILE   CHEMISTRY. 

The  color  solution  of  madder  is  best  prepared  by  boiling  the 
rasped  wood  in  water  and  straining  through  cheese-cloth,  making 
use  of  the  clear  solution  for  the  dye-bath.  The  colors  obtained 
on  the  various  mordants  are  not  as  clear  and  bright  as  those 
produced  from  alizarin.  The  use  of  calcium  acetate  in  the  dye- 
bath  serves  the  purpose  of  brightening  the  color;  in  case  the  water 
contains  considerable  lime  this  addition  need  not  be  made,  but 
sufficient  acetic  acid  should  be  added.  Madder  may  be  dyed  in  a 
single  bath,  using  5  per  cent,  of  alum,  4  per  cent,  of  tartar,  4  per 
cent,  of  calcium  acetate,  and  10  per  cent,  of  madder;  enter  the 
material  cold  and  slowly  bring  to  the  boil,  and  maintain  at  that 
temperature  for  one  hour.  This  method  is  used  only  for  the  dyeing 
of  light  colors,  as  otherwise  there  would  be  considerable  precipi- 
tation of  coloring-matter  in  the  dye-bath.  A  pale  brownish  drab 
stain  on  wool  may  be  produced  by  boiling  with  a  decoction  of 
madder  with  the  use  of  any  mordant  whatever.  This  method, 
in  fact,  has  been  used  in  practice.  The  colors  produced  with 
madder  on  either  a  chromium  or  an  aluminium  mordant  may  be 
considerably  brightened  by  the  addition  of  a  small  amount  of 
tin  crystals  to  the  mordanting  bath.  In  order  to  fully  develop 
the  coloring  power  of  madder  it  is  necessary  that  the  temperature 
of  the  dye-bath  be  gradually  and  regularly  elevated  to  the  boil- 
ing point.  The  addition  of  a  small  amount  of  sumac  (or  other 
tannin  extract)  to  the  dye-bath  serves  to  give  better  exhaustion 
of  the  coloring-matter. 

3.  Archil.  —  This  coloring-matter  is  obtained  from  certain 
species  of  lichens,  the  principal  varieties  of  which  are  Roccella 
tinctoria,  Roccella  fuciformia,  and  Variolaria  orcina.  The  dye- 
stuff  occurs  in  the  form  of  a  paste,  and  is  prepared  by  treating  the 
lichens  to  a  process  of  oxidation  in  the  presence  of  ammonia. 
The  principal  color-producing  compounds  existing  in  the  lichens 
are  erythrin,  lecanoric  acid,  and  evernic  acid.  The  lichens  are 
torn  up  into  small  fragments,  placed  in  iron  drums  provided  with 
stirrers,  and  mixed  with  'a  dilute  solution  of  ammonia.  The 
temperature  is  kept  at  about  100°  F.  for  several  days,  during  which 
time  the  mass  undergoes  a  fermentation  which  causes  the  develop- 


THE  MINOR   NATURAL  DYES.  22/ 

ment  of  the  coloring-matter.  When  the  latter  ceases  to  increase 
(which  is  determined  by  making  tests  from  time  to  time)  the 
fermentation  is  stopped.  The  product  so  obtained  is  archil 
paste;  archil  liquor  is  prepared  by  removing  the  fibrous  matter  of 
the  plant.  French  purple  is  a  preparation  of  archil  which  is  said 
to  give  faster  shades  than  the  ordinary  product;  it  is  made  by 
treating  the  lichens  with  a  dilute  solution  of  ammonia,  acidulating 
the  resulting  liquid  with  hydrochloric  acid,  which  precipitates 
the  coloring-matters.  This  precipitate  is  washed,  dissolved  in 
strong  ammonia,  and  kept  for  about  three  weeks  at  a  temperature 
of  1 60°  F.,  during  which  time  a  fine  purple  color  is  developed; 
calcium  chloride  is  added  and  a  purple  lake  is  precipitated. 
When  used  for  dyeing  this  lake  is  mixed  with  an  equal  weight  of 
oxalic  acid  and  dissolved  in  water. 

A  solution  of  archil  gives  the  following  reactions: 

Acids:    Solution  yellower. 

Alkalies:    Solution  bluer. 

Lead  acetate:    Crimson  precipitate. 

Calcium  chloride:    Red  precipitate. 

Stannous  chloride:    First  redder,  then  yellower. 

Alum:    Solution  redder. 

Basic  alum:    Crimson-red  precipitate. 

The  coloring  principle  of  prepared  archil  is  known  as  orcein. 

Archil,  or  orchil,  was  formerly  prepared  by  treating  the  lichens 
with  water  containing  putrid  urine,  and  at  a  subsequent  stage 
with  slaked  lime.  Archil  is  chiefly  employed  for  the  dyeing  of 
carpet  yarns. 

Archil  occurs  in  trade  in  three  forms:  (i)  as  a  thick  liquor 
called  archil;  (2)  as  a  paste  called  persis;  and  (3)  as  a  reddish 
brown,  or  purple  powder  termed  cudbear.  The  liquor  varies  in 
specific  gravity  from  8°  to  20°  Tw.;  the  paste  is  usually  a  35  per 
cent,  one,  but  is  sometimes  as  low  as  20  per  cent.  Archil  is 
sometimes  adulterated  with  other  vegetable  coloring-matters 
such  as  logwood,  sapan,  Brazil-wood,  etc.,  and  also  with  coal-tar 
dyes,  especially  Magenta.  Pure  cudbear  is  obtained  from  a 


228  DYEING   AND    TEXTILE  CHEMISTRY. 

lichen  known  as  Lecanora  tartarea.  It  is  prepared  and  used  in 
exactly  the  same  manner  as  archil,  and  gives  the  same  colors;  it 
also  yields  the  same  reactions.  In  fact,  the  two  dyes  commer- 
cially are  not  distinguished. 

4.  Quercitron.  —  This  dyestuff  is  from  the  inner  bark  of  a 
species  of  oak,  the  botanical  name  of  which  is  Quercus  citrina  or 
Quercus   tinctoria.     It    is    found    principally    in    Pennsylvania, 
Georgia,  and  the  Carolinas.     Its  dyeing  properties  are  due  to  two 
principles,  quercitrin,  C36H38O20,  and  quercetin,  C24H36On.     The 
best   varieties  are  shipped  from  Philadelphia,  New  York,  and 
Baltimore;  the  Philadelphia  variety  being  the  most  highly  prized. 
It  is  principally  used  in  calico  printing  for  the  production  of 
compound  shades  in  conjunction  with  mordants  of  aluminium, 
tin,  chromium,  and  iron.     It  is  also  employed  in  woolen  printing. 
In  the  dry  condition,  quercitron  is  of  a  yellow  or  buff  color,  being 
a  mixture  of  the  fibres  with  a  fine  powder  of  a  bitter  and  astringent 
taste.     The  extract  when  freshly  prepared  is  nearly  transparent 
and  of  a  dull  orange-red  color,  which  on  standing  deposits  a 
yellow  crystalline  powder,  and  becomes  turbid  and  considerably 
thicker.     The  extract  is  adulterated  chiefly  with  molasses.     In 
the  form  of  extract  it  is  known  as  bark  extract  and  is  usually  sold 
at  a  density  of  51°  Tw. 

Patent  bark  is  prepared  by  boiling  ground  quercitron  bark 
with  dilute  sulphuric  acid,  the  product  being  washed  and  dried. 
Its  chief  use  is  as  a  substitute  for  flavine  in  wool  dyeing. 

Flavine  is  a  very  pure  dry  extract  of  the  coloring-matter  of 
quercitron  bark.  The  best  varieties  contain  a  large  proportion 
of  quercetin,  and  yield  yellow  colors  of  great  brightness.  Flavine 
is  still  somewhat  used  in  conjunction  with  cochineal  for  the 
production  of  bright  yellowish  scarlet  colors. 

The  colors  obtained  from  quercitron  and  flavine  are  dulled 
by  prolonged  boiling  in  the  dye-bath  owing  to  the  presence  of 
considerable  tannin.  The  addition  of  glue  solution  is  beneficial 
in  this  respect. 

5.  Cutch.  —  Cutch,  or  catechu,  is  the  dried  extract  obtained 
from  several  Indian  trees,  a  species  of  Acacia,  the  chief  variety 


THE  MINOR   NATURAL  DYES.  229 

being  Acacia  catechu.  The  principal  varieties  are  Bombay, 
Bengal,  and  Gambier  cutch.  Bombay  cutch  is  obtained  from 
the  fruit  and  wood  of  the  Arcea  catechu,  a  kind  of  palm.  Bengal 
cutch  is  obtained  from  the  twigs  and  unripe  pods  of  the  Mimosa 
catechu.  The  above  two  varieties  are  very  similar  in  appearance, 
coming  into  commerce  in  the  form  of  large  blocks  of  a  dark  brown 
color,  weighing  from  30  to  40  pounds  and  packed  in  leaves. 
They  are  hard  but  brittle,  and  are  imported  from  Java,  Singapore, 
Peru,  and  the  East  Indies.  Gambier  cutch,  called  also  cubical 
or  yellow  cutch,  is  obtained  from  the  leaves  of  the  Uncaria 
gambier,  and  occurs  in  trade  in  the  form  of  small  cubes.  It  is 
much  more  yellow  in  appearance  than  the  two  other  varieties 
and  is  also  much  less  soluble  in  cold  water.  It  has  a  dull  earthy 
fracture  and  is  porous.  The  best  variety  is  grown  in  Rhio,  in 
the  Isle  of  Brittany,  and  is  imported  from  Singapore.  Another 
variety  of  cutch  is  kino,  or  gum  kino,  which  is  obtained  from  the 
Pterocarpus  marsupium.  It  has  a  reddish  brown  color  and  a 
highly  lustrous  fracture. 

Cutch  contains  two  principal  coloring-matters,  catechin, 
C19H20O2,  and  catechu-tannic  acid,  C38H36O16.H2O.  It  is  chiefly 
used  in  cotton  dyeing  and  in  calico  printing  for  the  production  of 
brown  shades  or  as  a  tannin  mordant  to  be  topped  with  basic 
or  other  colors.  Good  qualities  of  cutch  should  not  contain  more 
than  5  per  cent,  of  ash  on  ignition,  nor  more  than  12  per  cent,  of 
matter  insoluble  in  alcohol.  It  is  frequently  adulterated  with 
starch,  dried  blood,  sand,  and  clay.  Starch  is  detected  by  treat- 
ing the  sample  with  alcohol,  filtering,  and  dissolving  the  residue 
in  hot  water,  cooling,  and  testing  for  starch  with  an  iodine 
solution.  Pure  cutch  gives  a  decided  green  color  with  solutions 
of  ferric  salts,  so  the  addition  of  other  tannin  matters  may  be 
recognized  by  the  modified  color  given  with  ferric  salts.  Sand, 
clay,  etc.,  are  easily  detected  by  making  up  a  decoction  of  the 
sample  and  observing  the  amount  of  insoluble  residue  which 
remains,  as  pure  samples  should  be  almost  entirely  soluble  in 
hot  water.  Blood  may  be  detected  in  a  similar  way  as  starch,  by 
treating  the  sample  with  alcohol,  the  residue  being  dried  and 


230  DYEING  AND    TEXTILE  CHEMISTRY. 

heated  in  a  test-tube,  when,  if  blood  is  present,  ammonia  and 
offensive  odors  are  given  off. 

As  already  mentioned,  cutch  contains  two  coloring  principles; 
the  one  is  soluble  in  cold  water  and  is  termed  catechu-tannic 
acid,  or  mimotannic  acid;  the  other  is  nearly  insoluble  in  cold 
water  and  is  termed .  catechin  or  catechuic  acid,  a  brown  amor- 
phous substance.  Catechu-tannic  acid  may  be  obtained  by 
boiling  pulverized  cutch  with  water,  allowing  the  solution  to 
stand  for  several  days,  when  the  catechin  separates  out  and  may 
be  filtered  off.  The  nitrate  is  evaporated  to  dryness  and  treated 
with  alcohol  to  remove  impurities.  The  product  is  a  reddish 
brown  powder  soluble  in  water  and  alcohol,  but  not  soluble  on 
dry  ether.  With  ferric  salts  it  gives  a  grayish  green  precipitate, 
and  gives  no  reaction  with  ferrous  salts.  Its  aqueous  solution 
is  precipitated  by  gelatin,  albumen,  and  sulphuric  acid.  Cutch 
may  contain  from  35  to  55  per  cent,  of  catechu-tannic  acid, 
according  to  its  source.  With  alkalies  catechu-tannic  acid  forms 
soluble  salts,  the  solutions  of  which  rapidly  oxidize  on  exposure 
to  the  air  and  become  of  a  reddish  color. 

Catechin  forms  that  part  of  cutch  insoluble  in  cold  water. 
It  is  obtained  in  the  pure  state  by  taking  the  solid  which  separates 
out  after  boiling  cutch  with  water  and  cooling;  it  is  purified  by 
redissolving  in  hot  water,  boiling  with  animal  charcoal  to  decolor- 
ize it,  filtering  hot,  and  allowing  to  cool.  These  operations  may 
have  to  be  repeated  several  times.  The  product  obtained  is  in 
the  form  of  white  silky  crystalline  needles,  which  are  very  slightly 
soluble  in  water.  Catechin  precipitates  albumen,  but  not  gelatin. 
When  dissolved  in  concentrated  sulphuric  acid  it  gives  a  purplish 
colored  solution.  Though  sometimes  called  catechuic  acid, 
catechin  has  no  acid  properties,  and  is  neutral  to  litmus.  When 
dissolved  in  solutions  of  alkaline  carbonates  it  rapidly  absorbs 
oxygen  from  the  air  and  becomes  dark  red  in  color;  and  on  the 
addition  of  an  acid  dark  red  rubinic  acid  is  precipitated.  If 
caustic  alkalies  are  used  as  the  solvent,  then  a  very  dark  brown, 
nearly  black,  precipitate  of  japonic  acid  is  obtained  under  similar 
conditions.  This  same  substance  is  formed  when  a  decoction  of 


THE   MINOR   NATURAL   DYES. 

cutch  is  oxidized  with  potassium  bichromate;  and  in  fact,  it  is  on 
this  property  that  the  dyeing  powers  of  cutch  depend. 

Dyers  utilize  the  coloring  properties  of  both  catechin  and  the 
catechu-tannic  acid,  but  the  calico  printer  requires  chiefly  the 
catechin.  In  general,  cutch  is  used  in  cotton  dyeing  for  the  pro- 
duction of  browns  and  as  a  tannin  mordant;  it  is,  however, 
somewhat  used  in  woolen  and  silk  dyeing,  being  employed  in 
the  latter  chiefly  as  a  weighting  and  mordanting  agent  in  the 
production  of  blacks.  It  is  also  used  for  the  dyeing  and  pre- 
serving of  sails  and  fishing  nets,  as  well  as  in  medicine  as  an 
astringent,  and  also  in  the  tanning  of  leather. 

Cutch  is  best  applied  to  cotton  by  boiling  the  goods  in  a  de- 
coction of  the  dyestuff  and  then  allowing  to  stand  for  some  time 
after  which  the  cotton  is  taken  out,  squeezed,  and  worked 
in  a  hot  bath  containing  potassium  bichromate,  which  acts  on 
the  soluble  catechin  and  catechu-tannic  acid  to  produce  insol- 
uble japonic  acid  on  the  fibre.  Some  dyers  enter  the  cotton  into 
a  hot  bath  of  cutch,  then  work  it  for  some  hours  without  further 
application  of  heat,  and  treat  it  as  before  with  chrome.  It  is 
possible  to  use  bluestone  instead  of  chrome,  and  if  the  color  is 
developed  by  the  former  it  appears  much  yellower  and  not  quite 
so  full  in  shade  as  the  colors  produced  by  the  latter.  If  blue- 
stone  is  used  it  is  the  better  plan  to  add  it  directly  to  the  bath 
containing  the  cutch,  and  afterwards  to  develop  in  the  usual  way 
with  chrome.  In  the  latter  case,  the  shades  are  fuller  and  faster 
to  light  than  would  be  the  case  if  no  bluestone  were  used.  Cop- 
peras may  also  be  added  to  the  bath  for  the  purpose  of  darkening 
the  shade.  It  is  advisable  when  dyeing  very  dark  cutch  browns 
to  first  work  in  a  fairly  weak  bath,  develop  in  the  chrome  and 
afterwards  work  in  the  cutch  bath  again,  and  again  develop  with 
chrome,  and  repeat  this  until  the  required  depth  of  shade  is 
obtained.  By  this  means,  darker,  fuller,  and  more  level  shades 
may  be  obtained  than  by  using  very  strong  solutions  of  cutch. 
This  method  is  especially  applicable  to  the  dyeing  of  warps  and 
cotton  pieces.  It  should  be  noted  that  the  presence  of  copper  in 
the  color-lake  appears  to  make  it  faster  to  light.  Instead  of  using 


232  DYEING   AND    TEXTILE   CHEMISTRY. 

the  copper  sulphate  directly  in  the  cutch  bath,  as  is  usually 
done,  the  cotton  may  be  worked  in  a  cold  solution  of  the  salt, 
either  on  coming  out  of  the  cutch  bath  or  after  being  developed. 
Though  chrome  and  bluestone  are  the  chief  metallic  salts  employed 
for  fixing  cutch  in  cotton  dyeing,  other  salts  may  also  be  used. 
Aluminium  salts  give  a  yellowish  brown  color,  while  tin  salts  give  a 
still  yellower  color;  copperas  gives  a  brownish  gray.  Cotton  dyed 
with  cutch  has  the  property  of  being  afterwards  dyed  with  the 
basic  and  with  alizarin  (or  natural)  dyestuffs.  In  the  former 
case  it  is  the  catechu-tannic  acid,  or  the  products  formed  from  it 
by  oxidation,  that  act  as  the  mordant;  in  the  latter  case  it  is  the 
chromium  or  copper  fixed  in  the  fibre  which  acts  as  the  mordant. 
It  is  apparent,  therefore,  that  if  the  tone  of  a  cutch  brown  has  to  be 
altered  this  may  be  accomplished  by  any  suitable  dyestuff  of  the 
above  groups.  In  the  case  of  the  coloring-matters  requiring  a 
metallic  mordant,  the  dyestuff  may  be  added  directly  to  the  cutch 
bath,  when,  of  course,  the  color  produced  by  it  would  be  developed 
at  the  same  time  as  the  cutch.  With  the  basic  colors,  however, 
it  would  be  necessary  to  first  dye  the  cutch  brown  and  then  top 
off  in  a  separate  bath  with  the  basic  color. 

At  the  present  time  cutch  is  very  little  used  as  a  dyestuff  for 
wool,  although  for  the  production  of  certain  brown  shades  it  might 
be  employed  with  advantage.  The  objections  to  the  use  of  cutch 
are  several:  (a)  The  wool  acquires  a  harsh  feel;  this  might  be 
remedied  to  a  certain  extent  by  using  only  the  catechin,  but  this  is 
too  expensive,  (b)  The  best  and  fastest  shades  are  produced 
by  the  so-called  " saddening"  process;  that  is,  first  boiling  the 
wool  with  the  coloring  matter  and  then  fixing  in  a  fresh  bath 
with  a  solution  of  a  metallic  salt.  As  this  process  is  not  a  very 
convenient  one  for  dyeing  to  shade,  it  is -easy  to  understand  why 
cutch  is  not  much  used.  The  manner  of  dyeing  wool  with  cutch 
is  very  similar  to  that  for  the  dyeing  of  cotton,  except  that  boiling 
solutions  are  used.  Cutch  may  also  be  used  on  wool  in  conjunc- 
tion with  such  dyes  as  barwood  and  camwood.  By  first  mor- 
danting with  chrome  or  other  metallic  salt  (bluestone  or  copperas) , 
lighter  shades  are  obtained  than  when  the  saddening  method  is 


THE   MINOR   NATURAL  DYES.  233 

used.  The  colors  obtained  with  chrome  are  fairly  fast  to  light 
and  milling,  and  by  the  addition  of  a  little  bluestone  to  the  cutch 
bath  these  properties  are  increased. 

In  silk  dyeing  cutch  is  used  for  two  purposes.  One  is  for  the 
dyeing  of  silk  plush  an  imitation  of  sealskin;  in  which  case  the 
silk  is  dyed  in  a  similar  manner  to  cotton.  The  second  is  the  use 
of  cutch  in  black  dyeing,  when  the  method  is  to  first  mordant 
the  silk  with  nitrate  of  iron,  and  dye  with  Prussian  blue,  after 
which  the  silk  is  worked  in  a  strong  decoction  of  cutch,  or  better, 
gambier,  to  which  may  be  added  a  small  amount  of  tin  crystals. 
The  silk  absorbs  a  large  percentage  of  catechin,  and  is  then  mor- 
danted with  pyrolignite  or  nitrate  of  iron  and  dyed  in  the  usual 
manner.  This  method  is  used  in  the  production  of  the  so-called 
"  Lyons  "  black,  where  it  is  desired  to  weight  the  silk  about 
10  per  cent. 

6.  Cochineal.  —  This  coloring-matter  is  derived  from  an 
animal  source.  It  consists  of  the  bodies  of  the  female  insects 
known  as  Coccus  cacti;  they  are  found  in  Mexico  and  Central 
America  and  other  tropical  and  sub-tropical  countries,  and  grow 
on  certain  kinds  of  cactus.  At  the  proper  time  the  insects  are 
collected  and  killed  by  being  steamed  or  dried  in  hot  stoves;  the 
former  gives  the  black  cochineal  and  the  latter  the  silver  cochineal. 

The  coloring  principle  of  cochineal  is  carminic  acid.  The 
aqueous  solution  of  cochineal  yields  the  following  reactions: 

Acids:  Yellowish  color. 

Alkalies:    Violet  color. 

Lime-water:    Violet  precipitate. 

Alum:    Slowly  forms  red  precipitate. 

Aluminium  chloride:     Reddish  violet  precipitate. 

Stannous  chloride:    Violet  precipitate. 

Stannic  chloride:    Bright  scarlet  color. 

Ferrous  sulphate:    Violet  gray  precipitate. 

Copper  sulphate:    Violet  precipitate. 

Lead  acetate:    Violet  precipitate. 

Zinc  sulphate:    Violet  precipitate. 

Oxalic  acid:    Red  precipitate. 


234  DYEING  AND    TEXTILE  CHEMISTRY. 

Cochineal  was  formerly  very  extensively  employed  for  the  pro- 
duction of  bright  scarlets  and  reds  on  wool;  it  is  still  used  to  some 
extent  for  this  purpose,  but  has  been  largely  replaced  fry  the  acid 
scarlets.  The  scarlet  cloth  for  the  English  army,  however,  is 
still  dyed  with  cochineal.  In  cotton  dyeing  cochineal  has  no 
application,  though  small  quantities  are  used  in  printing.  Coch- 
ineal gives  the  following  colors  with  the  different  mordants: 

Chromium:  Purple. 
Aluminium:  Crimson. 
Iron:  Purple. 
Copper:  Claret. 
Tin:  Scarlet. 

The  principal  colors  are  the  crimson  with  alum  and  the  scarlet 
with  tin.  Cochineal  scarlet  is  faster  to  light  than  the  acid 
scarlets;  it  is  also  quite  fast  to  washing  and  fulling,  but  becomes  a 
little  bluer,  though  it  does  not  bleed.  The  solution  of  the  coloring- 
matter  for  dyeing  is  best  prepared  by  boiling  the  powdered 
cochineal  insects  in  water  and  straining  the  solution. 

Ammoniacal  cochineal  is  a  preparation  obtained  by  steeping 
ground  cochineal  in  ammonia  water  for  several  days,  three  parts 
of  ammonia  being  used  for  one  part  of  cochineal.  A  chemical 
reaction  takes  place  resulting  in  the  formation  of  a  carminamide 
from  the  carminic  acid.  The  mixture  is  then  heated  to  drive  off 
the  excess  of  ammonia,  and  hydrated  aluminium  oxide  is  added, 
and  the  heating  continued  until  all  of  the  ammonia  is  removed; 
then  the  mass  is  pressed  into  cakes.  It  is  used  for  dyeing  purple 
and  crimson,  and  for  rose  reds  in  connection  with  ordinary 
cochineal.  Its  color  is  not  as  readily  affected  by  acids  as  that  of 
the  other  cochineal.  It  also  gives  a  fine  purple  precipitate  with 
oxychloride  of  tin. 

A  good  quality  of  cochineal  should  not  give  more  than  one  per 
cent,  of  ash  on  ignition.  It  is  frequently  adulterated  with  half 
exhausted  cochineal  which  is  made  to  resemble  white  or  silver 
cochineal  by  drying  and  agitating  with  barium  sulphate,  white 
lead,  etc.  Black'  cochineal  is  also  adulterated  with  black  iron, 


THE  MINOR  NATURAL  DYES. 

sand,  graphite,  and  black  oxide  of  manganese.  These  mineral 
adulterants  are  easily  detected  by  powdering  the  sample  and 
treating  with  water,  when  the  mineral  matters  will  in  most  cases 
fall  to  the  bottom.  Occasionally,  adulteration  is  practiced  by 
adding  extract  of  Brazil-wood.  This  may  be  detected  by  treating 
the  sample  with  water,  adding  an  excess  of  lime-water,  which 
completely  precipitates  the  coloring-matters  of  the  cochineal, 
while  if  Brazil-wood  is  present  the  filtered  liquid  will  have  a 
purple  or  violet  color.  The  value  of  different  samples  of  cochi- 
neal is  best  estimated  by  dissolving  a  given  weight  of  the  powdered 
samples  in  water  and  observing  the  amount  of  standard  alum 
solution  necessary  to  completely  precipitate  the  coloring-matters. 
A  more  accurate  method,  perhaps,  is  to  conduct  a  series  of 
comparative  dye-tests  using  test-skeins  of  woolen  yarn  previously 
mordanted  with  tin  or  alumina. 

Cochineal  carmine,  or  carmine  lake,  is  a  brilliant  red  pigment 
produced  by  precipitating  a  decoction  of  cochineal  with  alumina. 
Its  manufacture,  however,  is  still  maintained  as  a  trade  secret. 
It  contains  a  large  amount  of  alumina  and  lime,  combined  with 
a  certain  amount  of  nitrogenous  matter,  which  seems  to  be 
essential  to  its  formation.  It  is  chiefly  used  by  paper  stainers 
and  calico  printers.  Cochineal  carmine  is  liable  to  be  adulterated 
with  starch,  china  clay,  vermilion,  and  various  pigment  colors. 
These  additions  may  be  detected  by  treating  the  sample  with 
dilute  ammonia  water,  which  will  readily  and  completely  dissolve 
pure  samples,  while  if  any  of  the  above  named  substances  are 
present  they  will  be  left  as  insoluble  matters.  The  ash  should  be 
under  10  per  cent.,  and  the  water  should  not  be  over  20  per  cent. 
The  ash  should  be  examined  for  tin,  which  if  present  in  any 
considerable  amount  indicates  the  presence  of  Biebrich  Scarlet 
lake,  which  closely  resembles  cochineal  carmine  in  many  of  its 
properties,  and  is  somewhat  difficult  to  detect  in  small  quantities. 

Besides  the  usual  two-bath  process  of  dyeing  cochineal  a  one-bath 
method  may  also  be  used,  as  follows:  The  dye-bath  is  prepared 
with  6  per  cent,  of  oxalic  acid,  6  per  cent,  of  stannous  chloride, 
and  20  per  cent,  of  cochineal.  The  oxalic  acid  should  be  added 


236  DYEING   AND    TEXTILE   CHEMISTRY. 

before  the  tin  crystals,  otherwise  a  precipitate  of  stannous  oxy- 
chloride  will  occur  which  will  cause  loss  of  coloring-matter.  A 
deficiency  of  tin  causes  the  color  to  be  dull  and  bluer,  while  an 
excess  of  tin  gives  a  paler  scarlet.  The  one-bath  method  gives 
yellower  and  more  brilliant  shades  than  the  two-bath  process, 
though  more  cochineal  is  required.  The  presence  of  iron  or 
copper  in  the  dye-vat  should  be  avoided,  otherwise  the  scarlet 
will  be  much  dulled.  To  obviate  this  defect  arising  from  the 
use  of  copper  steam-pipes  in  the  dye-vat  a  piece  of  clean  tin  should 
be  placed  in  the  bath;  this  prevents  the  copper  from  being  dis- 
solved. For  the  production  of  very  yellow  tones  of  scarlet  it  is 
necessary  to  use  some  suitable  yellow  dyestuff  in  connection  with 
cochineal.  Flavine  was  generally  employed  for  the  purpose. 

SAMPLES. 

387.  Wool  dyed  with  fustic  on  chrome  mordant. 

388.  Wool  dyed  with  fustic  on  tin  mordant. 

389.  Wool  dyed  with  fustic  on  iron  mordant. 

390.  Wool  dyed  with  madder  on  chrome  mordant. 

391.  Wool  dyed  with  madder  on  aluminium  mordant. 

392.  Wool  dyed  with  madder  on  tin  mordant. 

393.  Wool  dyed  with  archil  in  neutral  bath. 

394.  Wool  dyed  with  archil  in  acid  bath. 

395.  Wool  dyed  with  quercitron  on  chrome  mordant. 

396.  Wool  dyed  with  flavine  on  tin  mordant. 

397.  Cotton  dyed  with  cutch. 

398.  Showing  effect  of  bluestone  in  dyeing  cutch. 

399.  Wool  dyed  with  cochineal  on  tin  mordant. 

400.  Wool  dyed  with  cochineal  on  aluminium  mordant. 

QUIZ  20. 

600.  Name  the  principal  minor  natural  dyestuffs.     What  colors  do  they 
yield,  and  on  what  fibres  are  they  chiefly  dyed  ? 

60 1.  Describe  the  method  of  dyeing  wool  with  fustic.     What  is  the  effect 
of  the  use  of  different  mordants  ?     How  does  the  fastness  of  fustic  to  washing 
and  light  compare  with  that  of  alizarin  yellow  ? 

602.  From  what  tree  is  fustic  obtained?    What  is  its  botanical  name? 
In  what  countries  does  it  grow  ? 

603.  What  colors  does  fustic  yield  with  the  different  mordants?     In  what 
forms  may  it  be  employed  ?     In  the  dyeing  of  what  colors  is  it  principally  used  ? 


THE   MINOR   NATURAL   DYES.  237 

604.  What  coloring-matters  are  present  in  fustic?     What  differences  do 
they  exhibit  ? 

605.  Describe  the  principal  reactions  given  by  a  solution  of  fustic. 

606.  In  what  forms  does  fustic  occur  in  trade  ?     With  what  is  fustic  extract 
chiefly  adulterated  ?     How  may  fustic  extracts  best  be  tested  ? 

607.  What  is  the  effect  of  boiling  the  dye-bath  too  long  when  using  fustic? 
Explain  the  reason  and  state  how  the  defect  may  be  prevented. 

608.  What  is   "young  fustic"?    How  does  it    compare  with    ordinary 
fustic  ?     Is  it  still  in  general  use  ? 

609.  What  is  madder?     Give  the  general  method  of  applying  it  to  wool. 
What  mordants  may  be  used,  and  how  do  the  different  mordants  affect  the 
color? 

610.  From  what  is  madder  obtained?     In  what  countries  was  it  largely 
cultivated  ?    What  dyestuff  has  now  replaced  madder  ? 

6 1 1 .  What  are  the  principal  coloring-matters  contained  in  madder?    Which 
is  the  most  important  constituent?     In  what  form  do  the  coloring-matters 
exist  in  the  madder  root,  and  how  are  they  developed? 

612.  How  may  alizarin  be  obtained  from  madder?     What  are  its  principal 
reactions?    How  may  it  be  converted  into  anthracene? 

613.  In  what  forms  was  madder  employed  in  dyeing?     How  is  garancin 
prepared,  and  how  does  it  compare  with  madder?    What  are  "garanceux"  and 
"flowers  of  madder"  ? 

614.  What  colors  does  madder  yield  with  the  different  metallic  mordants? 
In  what  dyeing  process  is  madder  still  somewhat  employed  ? 

615.  What  are  the  chief  varieties  of  madder?    What  is  "crop  madder" 
and  "muelle  madder"? 

6 1 6.  How  is  the  color  solution  of  madder  best  prepared?     How  do  the 
colors  obtained  with  madder  compare  with  those  from  alizarin  ? 

617.  How  may  madder  be  dyed  in  a  single  bath  ?    Why  cannot  this  method 
be  used  for  dyeing  heavy  shades? 

618.  How  may  the  color  obtained  on  an  aluminium  mordant  with  madder 
be  brightened  ?    What  is  the  effect  of  adding  sumac  to  the  dye-bath  ? 

619.  From  what  is  archil  obtained?    How  is  it  prepared?     What  is  the 
difference  between  archil  paste  and  liquor? 

620.  How  is  French  purple  prepared?     How  is  it  used  in  dyeing?     To 
what  other  dyestuff  is  archil  closely  related  ? 

621.  What  class  of  dye  may  archil  be  considered  with  respect  to  wool? 
What  color  does  it  give  ?     What  is  the  general  fastness  of  the  color  ? 

622 .  Give  the  method  of  dyeing  archil  on  wool.     What  is  the  effect  of  adding 
acid  to  the  bath? 

623.  What  is  the  chief  use  of  archil?    Is  it  used  in  cotton  dyeing?    How 
may  it  be  dyed  on  silk  ? 


238  DYEING  AND    TEXTILE  CHEMISTRY. 

624.  What  are  the  general  reactions -of  a  solution  of  archil  ?     By  what  other 
name  is  archil  known  ?    For  what  class  of  yarns  is  archil  principally  used  ? 

625 .  In  what  forms  does  archil  occur  in  trade  ?     How  does  cudbear  compare 
with  archil  ? 

626.  What  color  does  quercitron  give ?     From  what  is  it  obtained  ?    What 
is  flavine? 

627.  Give  the  method  for  dyeing  quercitron.     What  is  the  difference  in  its 
color  on  a  chrome  and  a  tin  mordant  ? 

628.  In  what  branch  of  dyeing  are  quercitron  and  flavine  still  somewhat 
used?    What  is  the  general  fastness  of  the  color? 

629.  What  is  patent  bark  and  how  is  it  prepared?    What  is  the  effect  of 
prolonged  boiling  in  the  dyeing  of  quercitron  and  flavine  ? 

630.  What  color  does  cutch  yield  ?    What  other  use  than  as  a  dyestuff  does 
it  possess  ?     On  what  fibres  is  cutch  dyed  ? 

631.  Give  the  general  method  of  dyeing  cutch  on  cotton.     How  does  the 
addition  of  bluestone  affect  the  dyeing? 

632.  From  what  is  cutch  obtained?     How  does  gambier  differ  from  Bom- 
bay cutch?     What  coloring-matters  does  cutch  contain?     What  is  formed 
when  cutch  is  oxidized  with  chrome  ? 

633.  What  would  be  the  effect  on  the  color  of  cutch  of  adding  copperas  in 
the  dyeing?    For  what  purposes  is  cutch  used  in  the  dyeing  of  silk? 

634.  Of  what  does  cochineal  consist?    What  is  the  difference  between 
"black"  and  "silver"  cochineal?    What  colors  does  cochineal  give  on  mor- 
dants of  tin  and  of  aluminium  ? 

635.  Give  the  method  of  dyeing  cochineal  scarlet  on  wool.     What  is  the 
general  fastness  of  the  color? 

636.  What  is  ammoniacal   cochineal?    How  is  it  prepared?    What  is 
cochineal  carmine? 

637.  What  adulterations  are  liable  to  be  found  in  samples  of  cochineal, 
and  how  would  you  conduct  tests  for  their  detection  ? 

638.  Give  the  method  of  dyeing  cochineal  by  a  one-bath  process.     The 
presence  of  what  metals  should  be  avoided  in  dyeing  cochineal  ?     How  are  very 
yellow  tones  of  cochineal  scarlet  obtained? 


SECTION  XXI. 

THE  MINERAL  DYESTUFFS. 

-Experiment  125.  Chrome  Yellow  on  Cotton.  —  Steep  a  test- 
skein  of  cotton  yarn  for  30  minutes  in  a  cold  bath  consisting  of 
a  5  per  cent,  solution  (5  grams  per  100  cc.)  of  lead  acetate. 
Squeeze  evenly,  and  pass  into  a  second  bath  consisting  of  a  i  per 
cent,  solution  (i  gram  per  100  cc.)  of  chrome;  work  cold  for 
30  minutes.  Squeeze  and  wash  in  fresh  water,  then  soften  by 
working  in  a  dilute  solution  of  a  cotton  softener  or  glycerin  and 
soap.  Finally  squeeze  and  dry  (401).  In  order  to  obtain 
heavier  colors  the  alternate  passages  through  the  baths  of  lead 
acetate  and  chrome  may  be  repeated  several  times.  In  place  of 
using  the  ordinary  acetate  of  lead  (sugar  of  lead)  the  subacetate 
is  preferred  by  some.  This  is  prepared  by  boiling  together 
10  parts  of  lead  acetate  and  6  parts  of  litharge  (lead  oxide)  with 
40  parts  of  water;  filter,  and  use  the  liquor  so  obtained,  diluting 
in  accordance  with  the  depth  of  color  desired. 

Chrome  yellow  is  formed  in  accordance  with  the  following 
reactions : 

2.Pb(C2H302)2  +  K2Cr207  +  H20  =  2PbCrO4  +  2HC2H3O2. 

Lead  Acetate  Chrome  Lead  Chromate      Acetic  Acid 

Chrome  yellow  may  be  applied  to  wool,  silk,  or  any  other 
fibre  in  the  same  manner  as  above  described  for  cotton,  but  it 
is  seldom,  if  ever,  used  in  these  fibres.  In  the  dyeing  of  chrome 
yellow  it  is  necessary  to  first  apply  the  lead  salt  and  then  the 
chrome;  if  the  reverse  procedure  is  followed  the  pigment  will  be 
precipitated  on  the  outside  of  the  fibres  in  a  loosely  adherent 
condition,  and  will  not  be  fast  to  washing.  In  dyeing  heavy 
shades,  in  order  to  get  the  most  even  results  and  the  fastest 
color,  it  is  best  not  to  use  more  concentrated  solutions  but  to 

239 


240  DYEING  AND    TEXTILE   CHEMISTRY. 

give  the  cotton  several  dips  successively  in  the  two  solutions 
until  the  desired  depth  of  shade  is  obtained.  To  obtain  the 
purest  shades  of  yellow,  it  is  best  to  have  the  chrome  bath 
slightly  acid,  for  if  the  latter  becomes  at  all  alkaline  the  resulting 
pigment  will  acquire  an  orange  tone.  On  this  account  it  is 
better  to  employ  the  bichromate  of  potash  rather  than  the  neutral 
chromate.  Chrome  yellow,  though  fast  to  light,  washing,  and 
acid,  is  quite  sensitive  to  the  action  of  sulphuretted  hydrogen, 
turning  dark,  owing  to  the  formation  of  black  lead  sulphide. 
As  the  air  of  cities,  especially  in  the  vicinity  of  factories,  and  the 
air  of  houses  heated  by  burning  coal,  always  contain  more  or 
less  sulphuretted  hydrogen,  this  accounts  for  the  gradual 
darkening  of  chrome  yellow  on  exposure.  This  discoloration 
can  be  prevented  to  a  considerable  extent  by  incorporating 
with  the  lead  salt  a  salt  of  zinc  or  cadmium,  the  sulphide  of 
the  former  being  white  and  that  of  the  latter  yellow  in  color. 
In  order  to  show  this  action,  add  to  the  bath  of  lead  acetate  used 
in  the  above  experiment  i  per  cent,  of  cadmium  nitrate;  then 
dye  a  second  skein  of  cotton  in  the  same  manner  as  the  previous 
one  (402).  Take  small  samples  of  the  two  skeins  and  place 
them  in  a  bottle,  the  air  of  which  contains  a  minute  quantity  of 
sulphuretted  hydrogen.  After  some  time  it  will  be  found  that 
the  first  sample,  dyed  with  the  lead  salt  alone,  has  become  per- 
ceptibly darkened,  whereas  the  second  sample,  containing  the 
addition  of  cadmium  salt,  is  not  altered.  Though  unaffected  by 
acids,  chrome  yellow  is  changed  to  an  orange  by  the  action  of 
alkalies;  even  lime-water  will  serve  this  purpose.  The  orange 
color  is  due  to  the  formation  of  a  basic  compound  of  lead  chromate. 
To  illustrate  this  action,  take  a  small  sample  from  the  skein 
dyed  with  chrome  yellow  and  boil  it  in  a  weak  solution  of  soda 
ash;  then  wash  and  dry.  It  will  be  found  to  have  changed  to 
an  orange  color.  Treatment  with  acid  will  in  turn  destroy  the 
orange  tone  and  restore  the  original  yellow  color;  this  may  be 
shown  by  steeping  the  sample  above  tested  in  a  dilute  solution 
of  sulphuric  acid,  when  the  color  of  the  original  chrome  yellow 
will  again  be  formed.  By  the  action  of  strong  caustic  alkalies, 


THE   MINERAL   DYESTUFFS.  241 

chrome  yellow  may  be  completely  discharged  or  dissolved  from 
the  fibre,  as  may  be  shown  by  taking  a  small  sample  from  the 
skein  dyed  with  this  color  and  boiling  it  in  a  solution  of  caustic 
soda,  when  it  will  be  found  to  become  rapidly  decolorized.  This 
reaction  is  very  useful  in  printing,  as  by  its  means  discharge 
effects  may  be  obtained. 

Experiment  126.  Chrome  Orange  on  Cotton.  —  As  already 
indicated  in  the  previous  experiment,  this  color  may  be  obtained 
by  forming  the  basic  chromate  of  lead  in  the  fibre  by  the  use  of 
lead  chromate  and  an  alkali.  Proceed  as  follows:  Work  a  test- 
skein  of  cotton  yarn  for  30  minutes  in  a  cold  bath  consisting  of  a 
5  per  cent,  solution  of  lead  acetate;  squeeze,  and  pass  into  a  second 
bath  consisting  of  a  i  per  cent,  solution  of  chrome  and  a  small 
quantity  of  caustic  soda.  Enter  cold  and  gradually  raise  to  the 
boil  for  a  few  minutes.  Wash  in  a  warm  dilute  soap  bath  (403). 

A  modification  of  the  above  method  is  to  use  the  basic  acetate 
of  lead  prepared  in  the  manner  prescribed  in  the  previous  experi- 
ment from  lead  acetate  and  litharge. 

The  chrome  orange  obtained  as  above  indicated  may  be  bright- 
ened somewhat  by  working  in  a  boiling  bath  containing  lime.  Dye 
a  second  skein  of  cotton  in  a  manner  similar  to  the  first,  repeating 
the  treatment  in  the  two  baths  three  times.  Squeeze  and  wash, 
then  work  for  15  minutes  at  the  boil  in  a  bath  containing  10  per 
cent,  of  lime  (quicklime).  Finally  wash  and  soap  as  before  (404)0 

By  a  stronger  or  weaker  treatment  with  alkali,  chrome  orange 
may  be  made  to  vary  in  shade  from  a  bright  yellowish  orange  to 
a  scarlet  red.  The  remarks  made  under  chrome  yellow  as  to  its 
fastness  and  reactions  with  various  agents  are  also  applicable  to 
chrome  orange. 

Both  chrome  yellow  and  chrome  orange  are  poisonous  sub- 
stances, and  may  give  rise  to  cases  of  poisoning  among  operatives 
handling  cotton  dyed  in  this  manner,  or  even  to  wearers  of  such 
fabrics.  These  dyes  may  be  tested  for  on  the  fibre  by,  boiling 
a  sample  in  caustic  soda  solution  and  then  adding  a  few  drops 
of  ammonium  sulphide  solution,  when  a  black  precipitate  of 
lead  sulphide  will  be  formed. 


242  DYEING   AND    TEXTILE   CHEMISTRY. 

Experiment  127.  Iron  Buff  on  Cotton.  —  This  color  is  pro- 
duced by  precipitating  a  hydrated  oxide  of  iron  (Fe2O3  •  H2O)  in 
the  fibre.  Proceed  as  follows:  Work  a  test-skein  of  cotton  yarn 
for  30  minutes  in  a  cold  bath  consisting  of  a  5  per  cent,  solution  of 
copperas  (ferrous  sulphate,  FeSO4).  Squeeze,  and  pass  into  a 
bath  containing  5  per  cent,  on  the  weight  of  the  cotton  of  soda 
ash;  work  for  15  minutes  at  i8o°F.  Wash  and  pass  through 
a  warm  dilute  soap  bath  (405),  The  reaction  takes  place  as 
follows  : 

2  FeSO4+  2  Na.COg-i-  O  =  Fe2O3  +  2  Na2SO4+  CO2. 


The  oxidation  of  the  iron  from  the  ferrous  to  the  ferric  condition 
is  effected  by  the  atmospheric  oxygen.  By  repeating  the  treat- 
ment with  the  two  baths  several  times  heavier  shades  of  brown 
may  be  obtained.  Instead  of  using  copperas  a  solution  of 
"nitrate  of  iron"  (basic  ferric  sulphate)  may  be  substituted,  or  a 
solution  of  ferric  chloride.  Another  method  of  procedure  is  as 
follows:  Work  a  skein  of  cotton  as  above  in  the  same  bath  of 
copperas;  squeeze,  and  pass  through  a  cold  weak  solution  of 
chloride  of  lime  containing  a  little  caustic  soda  for  10  minutes. 
Squeeze,  and  repeat  the  passage  through  the  two  baths  twice. 
This  should  give  quite  a  heavy  shade  of  brown  (406).  Wash 
well,  and  soap  as  before.  The  chloride  of  lime  oxidizes  the 
ferrous  salt  very  rapidly  to  the  ferric  condition;  it  also  forms  a 
certain  amount  of  oxy-cellulose  with  the  cotton  which  takes  up 
the  iron  compound  more  energetically  than  the  unmodified 
cotton.  Another  method  of  producing  iron  buff  on  cotton  is  to 
impregnate  the  material  with  the  solution  of  the  iron  salt  as 
before,  then  to  pass  it  through  a  bath  containing  milk  of  lime,  after 
which  it  is  squeezed  and  exposed  to  the  air  over-night.  This 
latter  operation  is  termed  "aging."  The  light  brown  shade 
obtained  with  iron  oxide  is  also  known  as  nanking  and  chamois. 
The  brown  color  of  the  natural  Nanking  cotton  is  no  doubt  due 
to  its  containing  oxide  of  iron.  Iron  buff  on  cotton  is  exceedingly 
fast  to  light,  washing  and  alkalies,  and  also  to  exposure;  it  is 
decolorized,  however,  with  acids,  which  may  be  shown  by  steep- 


THE   MINERAL   DYESTUFFS.  243 

ing  a  small  sample  of  the  dyed  skein  in  a  warm  dilute  solution 
of  hydrochloric  acid.  In  calico  printing  iron  buff  may  be  dis- 
charged white  with  citric  acid  or  with  a  solution  of  stannous 
chloride  in  hydrochloric  acid. 

As  iron  oxide  forms  a  good  mordant  with  the  alizarin  and 
natural  dyestuffs,  iron  buff  on  cotton  may  be  topped  off  with 
these  dyestuffs  and  quite  an  extensive  variety  of  shades  produced 
thereby.  In  order  to  illustrate  this  procedure,  dye  three  skeins 
of  cotton  a  light  shade  of  iron  buff  in  the  manner  above  indicated. 
Top  off  the  first  one  in  a  bath  containing  2  per  cent.  Alizarin  Red 
(407),  the  second  one  with  2  per  cent.  Alizarin  Blue  (408),  and 
the  third  one  with  5  per  cent,  fustic  extract  (solid)  (409).  Enter 
at  a  low  temperature  and  gradually  raise  to  the  boil.  Wash  and 
soap  in  the  manner  before  described. 

Experiment  128.  Iron  Gray  on  Cotton.  —  This  color  is 
obtained  by  precipitating  tannate  of  iron  within  the  fibre.  Pro- 
ceed as  follows:  Work  a  skein  of  cotton  for  30  minutes  in  a  cold 
bath  of  nitrate  of  iron  at  2°  Tw. ;  squeeze,  and  pass  into  a  bath 
containing  5  per  cent,  of  tannic  acid;  work  cold  for  15  minutes. 
Wash  and  soap  in  the  usual  manner  (410).  Deeper  shades  of 
gray  and  slate  may  be  obtained  by  repeating  the  treatment 
several  times.  The  operations  may  also  be  reversed  and  the 
treatment  with  the  tannic  acid  may  take  place  first,  as  in  the 
usual  manner  of  mordanting  cotton  for  the  purpose  of  dyeing 
heavy  colors  with  the  basic  dyes.  Besides  tannic  acid  itself  the 
various  natural  tannins  may  be  employed,  such  as  sumac,  cutch, 
chestnut  extract,  etc.,  in  which  cases  the  resulting  color  will  be 
modified  by  the  addition  of  the  natural  color  of  the  tannin.  By 
using  rather  concentrated  baths  and  repeating  the  operations 
several  times,  cotton  may  be  dyed  black  by  this  method.  In 
fact,  before  the  introduction  of  logwood,  this  was  the  chief  method 
for  the  dyeing  of  black  on  cotton.  Iron  gray  on  cotton  is  quite 
fast  to  light  and  washing;  on  long  exposure  it  turns  rusty,  owing 
to  the  gradual  formation  of  iron  oxide;  it  also  turns  brown  on 
treatment  with  alkalies  for  the  same  reason.  Like  iron  buff  it  is 
also  decolorized  by  the  action  of  acids. 


244  DYEING  AND   TEXTILE  CHEMISTRY. 

Experiment  129.  Manganese  Brown  on  Cotton.  —  This  color 
is  also  known  as  "  bistre,"  and  is  formed  by  precipitating  an 
oxide  of  manganese  in  the  fibre.  Proceed  as  follows:  Work  a 
skein  of  cotton  for  30  minutes  in  a  cold  bath  consisting  of  a 
5  per  cent,  solution  of  manganese  chloride;  squeeze  and  pass  into 
a  cold  bath  containing  10  per  cent,  of  caustic  soda;  work  for 
15  minutes;  wash  in  fresh  water,  and  then  pass  into  a  dilute  bath 
of  chloride  of  lime  (about  i°  Tw.) ;  finally  wash  well  and  soap 
in  the  usual  manner  (411).  In  the  treatment  with  caustic  soda 
there  is  precipitated  in  the  fibre  a  hydrate  of  manganese;  a 
dilute  bath  of  soda  ash  may  also  be  used  for  the  same  purpose. 
The  final  treatment  with  chloride  of  lime  is  for  the  purpose  of 
oxidizing  the  compound  to  the  higher  oxide  of  manganese.  The 
resulting  compound  is  probably  Mn2O3  and  consists  of  a  mixture 
of  manganese  dioxide,  MnO2,  and  manganous  oxide,  MnO. 
Bistre  was  formerly  a  very  important  color  for  cotton  and  exten- 
sively used  both  in  dyeing  and  printing.  It  is  very  fast  to  light, 
washing,  and  alkalies;  it  is  also  fast  to  dilute  acids,  but  strong 
acids  decolorize  it,  as  also  do  reducing  agents.  Bistre  may  also 
be  dyed  on  cotton  by  passing  the  material  saturated  with  the 
solution  of  manganese  chloride  into  a  bath  containing  a  mixture 
of  caustic  soda  and  chloride  of  lime,  an  operation  which  then 
dispenses  with  the  use  of  a  third  bath.  The  use  of  soda  ash  in 
place  of  the  caustic  soda  cannot  be  recommended,  as  the  pre- 
cipitate produced  contains  manganese  carbonate,  which  is  not  as 
readily  oxidized  as  the  hydrate.  The  final  dyeing  is  also  apt  to 
come  out  rather  uneven.  Bistre  can  also  be  produced  on  cotton 
by  the  use  of  potassium  permanganate,  as  may  be  shown  in  the 
following  manner:  Work  a  skein  of  cotton  for  15  minutes  in 
a  cold  bath  containing  2  per  cent,  of  potassium  permanganate. 
The  cotton  will  be  found  to  turn  brown  rapidly  on  exposure  to 
the  air;  squeeze,  wash,  and  soap  in  the  usual  manner  (412). 
Manganese  brown  is  decolorized  by  treatment  with  either 
hydrogen  peroxide  or  sulphurous  acid;  wherein  it  differs  from 
the  brown  obtained  from  iron  oxide.  In  order  to  show  this 
behavior,  take  a  small  sample  each  of  iron  buff  and  bistre  and 


THE    MINERAL  DYESTUFFS.  245 

steep  them  for  several  hours  in  a  solution  of  hydrogen  peroxide; 
also  steep  two  similar  samples  in  an  acidified  solution  of  sodium 
bisulphite.  It  will  be  found  that  the  samples  of  bistre  are  more 
or  less  completely  decolorized,  while  the  samples  of  iron  buff  are 
not  much  altered.  Bistre  may  be  employed  as  the  basis  for  the 
production  of  aniline  black  on  cotton,  proceeding  as  follows: 
Take  a  skein  of  cotton  dyed  a  full  shade  of  brown  with  bistre 
in  the  manner  above  described,  and  work  it  in  a  cold  bath  con- 
taining 10  per  cent,  of  aniline  salt;  then  gradually  bring  to  the 
boil.  Squeeze,  wash  thoroughly,  and  soap  in  the  usual  manner 
(413).  This  black  is  very  fast  to  washing.  By  using  para- 
phenylene-diamine  or  beta-naphthylamine,  a  very  good  shade 
of  brown  may  be  obtained  which  does  not  differ  much  in  color 
from  the  original  bistre,  but  it  is  fast  to  acids.  With  alpha- 
naphthylamine  a  plum  color  is  produced.  Cotton  cloth  dyed 
with  bistre  has  the  property  when  subsequently  dyed  in  the 
indigo  vat  of  taking  up  a  greater  amount  of  indigo  and  fixing 
it  faster  to  washing  than  ordinary  cotton.  Bistre  is  sometimes 
used  in  dyeing  of  mohair  plush  in  order  to  give  a  fabric  in 
imitation  of  a  natural  fur  pelt,  the  cotton  back  being  dyed  with 
cutch  brown  in  the  yarn,  while  the  mohair  pile  is  woven  from 
undyed  yarn.  The  plush  is  then  treated  with  a  solution  of 
potassium  permanganate,  which  rapidly  dyes  the  mohair  brown 
and  also  colors  the  cotton  back  a  fuller  shade.  As  soon  as  the 
desired  shade  is  obtained  the  material  is  washed  and  dried. 
Then  by  the  use  of  rotating  brushes  a  suitably  thickened  solution 
of  sodium  bisulphite  is  applied  to  the  ends  of  the  mohair  pile, 
which  causes  the  brown  color  to  become  discharged,  and  thereby 
imitate  more  closely  the  appearance  of  the  natural  pelt.  In  order 
to  show  the  use  of  bistre  on  woolen  material,  take  a  skein  of 
wool  and  pass  it  through  a  cold  bath  containing  2  per  cent,  of 
potassium  permanganate;  work  for  15  minutes;  then  squeeze 
and  wash  well  (414). 

According  to  certain  chemists,  the  irregularity  which  some- 
times arises  in  manganese  brown  is  due  to  the  physical  condition 
of  the  precipitate  itself.  In  order  to  overcome  such  defects,  it 


246  DYEING  AND    TEXTILE  CHEMISTRY. 

has  been  recommended,  after  impregnating  the  cotton  with  the 
manganese  salt,  to  pass  it  through  a  bath  containing  ammonia 
and  potassium  bichromate,  whereby  a  rather  unstable  manganese 
chromate  is  precipitated  in  the  fibre;  this  gradually  decomposes, 
and  the  chromic  acid  liberated  reacts  with  manganous  hydrate, 
forming  the  higher  oxide  of  manganese.  The  oxidation  is 
completed  by  passing  the  cotton  through  a  dilute  bath  of 
bleaching  powder. 

Experiment  130.  Chrome  Green  on  Cotton.  —  A  pale  dull 
shade  of  green  can  be  obtained  on  cotton  by  precipitating  on 
the  fibre  oxide  of  chromium,  Cr2O3.  Proceed  as  follows:  Work 
a  test-skein  of  cotton  for  30  minutes  in  a  cold  bath  consisting  of 
a  10  per  cent,  solution  of  chrome  alum;  squeeze,  and  pass  into  a 
bath  containing  10  percent,  of  soda  ash;  enter  cold  and  gradu- 
ally bring  to  the  boil.  Wash  well  and  soap  in  the  usual  manner 
(415).  By  repeating  the  operations  several  times  fuller  shades 
may  be  obtained.  ,  Chromium  oxide  gives  a  sea-green  color  on 
cotton  which  is  exceedingly  fast  to  light,  washing,  and  alkalies; 
it  is  also  fast  to  exposure,  but  is  decolorized  by  the  action  of  acids. 
The  color  of  chrome  green  may  be  brightened  somewhat  by 
passing  the  dyed  cotton  through  a  bath  of  dilute  copper  sulphate 
(the  bath  should  be  very  dilute  and  warm).  Chrome  green  is 
seldom  used  at  the  present  time  as  a  self  color  on  cotton,  but 
it  has  had  extensive  use  in  conjunction  with  iron  buff  for  the 
production  of  the  so-called  khaki  color  with  which  the  service 
uniform  of  the  army  is  dyed.  In  order  to  obtain  this  khaki 
color  proceed  as  follows:  Work  a  test-skein  of  cotton  in  a  cold 
bath  consisting  of  a  5  per  cent,  solution  of  ferric  chloride  with 
a  5  per  cent,  solution  of  chrome  alum,  then  pass  into  a  bath  con- 
taining 10  per  cent,  of  soda  ash;  enter  cold  and  gradually  bring 
to  the  boil.  Wash  well,  and  soap  as  usual  (416).  By  vary- 
ing the  relative  amounts  of  iron  and  chromium  salts,  or  by  the 
addition  of  a  small  amount  of  manganese  salt,  the  shade  of  this 
khaki  color  may  be  varied  in  order  to  obtain  any  tone  desired. 

Experiment  131.  Prussian  Blue  on  Cotton  or  Wool. — The 
production  of  this  color  depends  on  the  precipitation  of  a  ferro- 


THE  MINERAL  DYESTUFFS.  247 

cyanide  of  iron  within  the  fibre.  On  cotton  it  is  dyed  as  follows : 
Work  a  test-skein  of  cotton  in  a  boiling  bath  of  nitrate  of  iron 
(32°Tw.)  also  containing  5  per  cent,  of  stannous  chloride;  steep 
for  30  minutes,  squeeze,  and  pass  into  a  bath  containing  10  per 
cent,  of  potassium  ferrocyanide  (yellow  prussiate  of  potash); 
work  warm  for  15  minutes;  then  pass  back  into  the  bath  of 
nitrate  of  iron  again;  finally  squeeze,  wash,  and  soften  in  a  soap 
bath  (417).  Heavier  shades  may  be  obtained  by  repeating  these 
operations  several  times;  the  cotton,  however,  should  always  be 
worked  last  in  the  bath  of  nitrate  of  iron  in  order  to  prevent  the 
formation  of  a  soluble  variety  of  Prussian  blue.  For  dyeing  wool 
proceed  as  follows :  Work  a  test-skein  of  wool  in  a  bath  containing 
10  per  cent,  of  potassium  ferricyanide  (red  prussiate  of  potash), 
20  per  cent,  of  sulphuric  acid,  and  i  per  cent,  of  stannous  chloride; 
enter  cold  and  gradually  raise  to  the  boil,  when  the  wool  will  turn 
green  and  finally  become  blue.  After  boiling  for  10  minutes, 
lift,  and  add  i  per  cent,  more  of  stannous  chloride,  and  work  for 
15  minutes  longer.  Finally  wash  well  in  fresh  water  (418). 
The  depth  of  shade  may  be  varied  by  employing  greater  or  less 
amounts  of  potassium  ferricyanide.  »  If  the  blue  color  does  not 
develop  properly  a  few  drops  of  nitric  acid  may  be  added  to  the 
bath  for  the  purpose  of  accelerating  the  oxidation.  Another 
method  of  dyeing  this  color  on  wool  is  to  use  .15  to  20  per  cent,  of 
potassium  ferrocyanide  with  the  addition  of  a  small  amount  of 
alum  and  tartar  to  the  bath. 

Prussian  blue  also  goes  by  the  name  of  Berlin  blue;  it  was 
formerly  a  very  important  color,  both  for  cotton  and  wool, 
and  is  even  still  used  to  a  considerable  extent,  especially  in  print- 
ing. Before  the  introduction  of  Alizarin  Blue  it  was  extensively 
employed  for  the  dyeing  of  army  uniforms.  Prussian  blue 
appears  to  be  a  complicated  cyanogen  compound  of  iron,  the 
exact  tone  of  which  varies  considerably  with  the  manner  of  its 
production.  Though  not  now  employed  as  a  self  color  in  dyeing 
of  silk,  Prussian  blue,  however,  is  still  used  as  a  bottom  color  in 
the  dyeing  of  weighted  black  on  this  fibre.  Prussian  blue  is 
fast  to  light,  washing,  and  exposure;  it  is  also  fast  to  dilute  acids, 


248  DYEING  AND    TEXTILE  CHEMISTRY. 

but  is  dissolved  by  stronger  acids,  also  by  a  concentrated  solution 
of  oxalic  acid.  With  caustic  alkali  it  is  decomposed  into  potas- 
sium ferrocyanide  and  brown  oxide  of  iron.  This  latter  reaction 
is  still  used  for  discharge  work  in  printing.  The  action  of 
stannous  chloride  in  the  dyeing  of  Prussian  blue  is  to  brighten 
and  give  a  reddish  tone  to  the  shade,  probably  due  to  the  forma- 
tion of  a  tin  ferrocyanide.  A  bright  green  color  on  cotton  may 
be  produced  by  the  combined  and  simultaneous  use  of  Prussian 
blue  and  chrome  yellow  in  the  following  manner:  Work  a  test- 
skein  of  cotton  in  a  cold  bath  containing  10  per  cent,  of  ferrous 
acetate  and  10  per  cent,  of  lead  acetate  for  30  minutes;  squeeze, 
and  pass  into  a  bath  containing  5  per  cent,  of  potassium  ferro- 
cyanide and  2  per  cent,  of  potassium  bichromate.  Squeeze,  wash 
well,  and  soap  as  usual  (419). 

Boiling  soap  solutions  decompose  Prussian  blue,  leaving  the 
brown  oxide  of  iron  on  the  fibre.  On  prolonged  exposure  to 
sunlight,  the  color  becomes  somewhat  lighter,  but  the  original 
tone  is  restored  on  being  kept  in  the  dark  for  some  time. 

The  theory  of  the  application  of  Prussian  blue  to  wool  is  that 
when  a  mineral  acid  is  added  to  a  solution  of  potassium  ferri- 
cyanide,  the  corresponding  hydro-ferricyanic  acid  is  liberated; 
this  under  the  influence  of  heat  and  oxidation  is  decomposed  with 
the  precipitation  of  Prussian  blue.  If  nitric  acid  is  employed  in 
the  bath,  the  shade  of  blue  is  somewhat  greener  than  when  the 
other  mineral  acids  are  used.  Yellow  prussiate  of  potash  may 
be  used  instead  of  the  red,  in  which  case  it  was  the  custom  of 
dyers  to  use  a  mixture  of  the  three  mineral  acids,  under  the  name 
of  "royal  blue  spirits,"  or  simply  "blue  spirits."  Nitric  acid  is 
the  best  acid  to  employ  in  connection  with  potassium  ferro- 
cyanide on  account  of  its  oxidizing  action.  The  stannous 
chloride  was  formerly  used  by  the  dyer  in  the  form  of  a  solution 
known  as  " muriate  of  tin"  or  " finishing  blue  spirits."  The 
solution  in  this  form  often  contained  sulphuric  and  oxalic 
acids. 


THE  MINERAL  DYESTUFFS.  249 

NOTES. 

i.  General.  —  There  are  a  few  mineral  compounds  which  are 
capable  of  being  used  for  the  dyeing  of  textile  fabrics.  Though 
formerly  of  considerable  importance,  this  class  of  colors  is  now 
nearly  obsolete  in  dyeing.  They  differ  very  radically  from  the 
vegetable  and  coal-tar  colors  in  that  they  are  of  mineral  nature 
and  are  not  organic  bodies.  As  a  rule,  they  are  exceedingly  fast 
to  light,  and  are  also  very  fast  to  washing.  The  general  method  of 
dyeing  these  colors  is  to  impregnate  the  fibre  with  a  solution  of 
some  metallic  salt,  and  subsequently  to  treat  it  with  a  solution 
of  another  compound  capable  of  yielding  a  colored  precipitate 
with  the  metal  already  present.  Lead  salts,  for  instance,  when 
added  to  potassium  bichromate  give  a  bright  yellow  precipitate 
of  chrome  yellow  (lead  chromate);  if  this  precipitation  is  pro- 
duced within  the  fibre  itself,  then  the  latter  will  become  dyed 
with  the  chrome  yellow.  Cotton  is  the  fibre  mostly  used  for  the 
application  of  the  mineral  colors,  the  only  color  which  is  applied 
to  wool  being  Prussian  blue.  All  the  mineral  dyes  make  the 
fabric  more  or  less  harsh  and  stiff;  this  may  be  remedied  some- 
what by  after-soaping,  or  by  using  a  cotton  softener  of  oil, 
but  it  can  never  be  removed  entirely.  Many  of  the  mineral 
compounds  used  in  the  preparation  of  these  colors  are  of  a  poison- 
ous nature,  which  is  a  great  drawback  to  their  use;  lead,  copper, 
arsenic,  mercury,  and  antimony  compounds  are  all  poisonous. 
As  many  of  the  metals  forming  the  basis  of  these  colors  also  serve 
as  mordants  with  alizarin  and  many  acid  dyes,  the  colors  obtained 
with  the  metallic  pigments  may  be  shaded  and  modified  by  the 
use  of  suitable  coal-tar  dyestuffs.  Loose  cotton  is  seldom  dyed 
with  the  mineral  colors,  as  it  then  becomes  difficult  to  card  and 
spin.  The  mineral  colors,  though  now  but  little  used  in  actual 
dyeing,  are  still  employed  rather  extensively  in  calico-printing. 
In  the  latter  they  are  used  in  connection  with  albumen  in  the 
color  pastes,  and  this  on  steaming  becomes  coagulated  and 
rendered  insoluble,  and  at  the  same  time  serves  to  fix  the  color 
on  the  cloth. 


250  DYEING  AND    TEXTILE  CHEMISTRY. 

The  mineral  colors  differ  in  the  principle  of  their  dyeing  from 
that  of  the  coal-tar  dyes  in  that  they  are  strictly  of  a  pigment 
character.  There  is  no  combination  between  the  coloring- 
matter  and  the  fibre  itself;  there  is  only  a  uniform  precipitation 
of  the  finely  divided  insoluble  pigment  throughout  the  cells  of 
the  fibre,  caused  by  the  chemical  double  decomposition  between 
the  two  soluble  salts  employed.  The  metallic  salt  is  absorbed 
by  the  fibre  from  its  solution  by  osmosis  into  the  cells  of  the 
latter;  as  the  osmotic  action  is  comparatively  slow,  in  order  that 
the  final  dyeing  be  thoroughly  penetrated,  it  is  advisable  to  allow 
the  cotton  to  steep  in  the  solution  of  the  metallic  salt  for  a  con- 
siderable time,  and  before  being  entered  in  the  bath  the  yarn  or 
cloth  should  be  thoroughly  wetted  out,  else  the  fibre  will  not 
become  completely  impregnated  with  the  salt.  After  thorough 
saturation  the  goods  may  even  be  rinsed  in  fresh  water  without 
fear  of  washing  out  the  metallic  salt  held  in  the  pores  or  cells  of 
the  fibre;  in  fact,  a  moderate  rinsing  may  be  considered  bene- 
ficial, as  it  serves  to  remove  the  excess  of  solution  adhering  to 
the  outside  of  the  fibres  and  between  the  interstices  of  the  fibres 
themselves,  as  this  is  not  removed  by  a  simple  squeezing  or 
wringing.  This  portion  of  the  metallic  salt  solution  not  held 
osmotically  by  the  fibre  would  come  off  to  a  certain  extent  in  the 
succeeding  bath  wherein  the  pigment  is  formed,  thus  causing  an 
unnecessary  consumption  of  chemicals,  and  the  contamination 
of  the  second  bath  with  a  precipitate.  There  would  also  be 
formed  a  loosely  adherent  precipitate  of  pigment  in  the  interstices 
between  the  fibres,  which  would  not  prove  fast  to  washing  or 
rubbing,  and  in  the  case  of  yarn  would  also  dust  off  in  the 
handling  thereof,  besides  adding  considerably  and  unnecessarily 
to  the  harshness  of  the  cotton.  The  action  of  the  second  or 
precipitating  solution  is  also  by  osmosis.  Taking  the  formation 
of  chrome  yellow  as  an  example,  the  solution  of  potassium 
bichromate  gradually  passes  by  osmosis  into  the  pores  of  the 
fibre,  where  it  comes  in  contact  with  the  lead  acetate  already 
present;  the  insoluble  chromate  of  lead  separates  out,  and  thus 
is  held  securely  in  the  pores  of  the  fibre,  while  the  second  member 


THE  MINERAL  DYESTUFFS. 

of  the  reaction,  the  potassium  acetate,  being  a  soluble  salt,  passes 
back  into  the  bath  again  by  osmosis. 

Most  of  the  mineral  colors  are  very  cheap  in  their  application, 
but  it  is  rather  difficult  to  dye  them  to  a  matched  shade.  Their 
exceptional  fastness  to  light  and  washing  is  their  principal 
advantage. 

2.  The  Minor  Pigment  Colors,  —  There  are  a  number  of 
metallic  pigment  colors  which  may  be  produced  in  the  fibre 
besides  the  ones  which  have  been  mentioned  in  the  foregoing 
.pages.  They  are,  however,  of  only  theoretical  value  and  possess 
no  practical  importance  to  the  dyer.  A  brown  color  may  be 
dyed  on  wool  by  working  it  in  a  bath  containing  lead  acetate  and 
lime;  the  sulphur  present  in  the  wool  combines  to  form  lead 
sulphide.  A  gray  color  on  cotton  may  be  produced  by  working 
the  latter  in  a  bath  containing  mercury  nitrate,  squeezing,  and 
passing  through  a  bath  containing  sodium  sulphide.  Cotton 
may  be  dyed  with  red  oxide  of  lead  by  steeping  in  a  bath  of  lead 
acetate  and  then  passing  through  a  bath  containing  a  mixture  of 
caustic  soda  and  chloride  of  lime.  A  blue  color  on  cotton  may 
be  obtained  by  working  in  a  bath  containing  ammonium  molyb- 
date  and  developing  in  a  bath  containing  stannous  chloride  and 
hydrochloric  acid.  A  yellow  color  on  cotton  or  wool  may  be 
obtained  by  the  use  of  titanium  salts  (see  the  application  of 
these  salts  in  mordanting) .  Cadmium  yellow  may  be  precipitated 
in  cotton  by  first  steeping  in  a  solution  of  cadmium  nitrate  or 
chloride  and  passing  through  a  bath  containing  sodium  sulphide. 
Scheele's  green  may  be  dyed  by  first  steeping  the  material  in  a 
solution  of  copper  sulphate,  then  passing  through  a  bath  of 
caustic  soda,  whereby  copper  hydrate  is  formed,  and  finally 
treating  with  a  solution  of  arsenious  acid,  resulting  in  the 
formation  of  green  copper  arsenite.  Another  green  may  be 
made  in  the  fibre  by  steeping  in  a  solution  of  chrome  alum, 
passing  through  a  bath  of  caustic  soda  and  finally  through  a 
bath  of  sodium  arsenite.  Both  of  these  green  colors  are  very 
poisonous. 


252  DYEING  AND    TEXTILE  CHEMISTRY. 

SAMPLES. 

401.  Chrome  yellow  on  cotton. 

402.  Chrome  yellow  with  cadmium  salt. 

403.  Chrome  orange  on  cotton. 

404.  Chrome  orange  brightened  with  lime. 

405.  Iron  buff  on  cotton. 

406.  Iron  buff  oxidized  with  chloride  of  lime. 

407.  Iron  buff  topped  with  Alizarin  Red. 

408.  Iron  buff  topped  with  Alizarin  Blue. 

409.  Iron  buff  topped  with  fustic. 

410.  Iron  gray  on  cotton. 

411.  Manganese  brown  on  cotton. 

412.  Bistre  dyed  with  potassium  permanganate. 

413.  Aniline  Black  dyed  on  bistre. 

414.  Bistre  dyed  on  wool. 

415.  Chrome  green  on  cotton. 

416.  Khaki  dyed  on  cotton. 

417.  Prussian  blue  on  cotton. 

418.  Prussian  blue  on  wool. 

419.  Green  on  cotton  with  Prussian  blue  and  chrome  yellow. 

QUIZ  21. 

639.  Of  what  does  chrome  yellow  consist?    How  is  it  applied  to  cotton? 
How  are  heavier  shades  obtained  ? 

640.  What  is  sugar  of  lead  ?     How  is  sub-acetate  of  lead  prepared  ?    What 
chemical  reaction  takes  place  in  the  dyeing  of  chrome  yellow  ? 

641.  On  what  fibres  is  chrome  yellow  dyed?    Why  is  it  necessary  to  use 
the  bath  of  lead  salt  first  ?    What  is  the  effect  on  the  color  if  the  chrome  bath 
becomes  alkaline  ? 

642.  What  is  the  general  fastness  of  chrome  yellow?    Why  is  it  not  fast  to 
exposure  in  city  air  ?    Explain  the  chemical  reaction  occurring. 

643.  How  may  the  discoloration  of  chrome  yellow  be  prevented?    What 
is  the  effect  of  alkalies  on  chrome  yellow  ?     Of  strong  caustic  soda  ? 

644.  How  is  chrome  orange  dyed  on  cotton?     Of  what  does  this  color 
consist  ? 

645.  How  may  chrome  orange  be  brightened?    Through  what  range  of 
color  may  chrome  orange  be  produced?    What  is  the  general  fastness  of 
chrome  orange  ? 

646.  What  may  be  said  regarding  the  poisonous  character  of  the  chrome 
colors  ?    How  may  they  be  tested  for  on  the  fibre  ? 

647.  Of  what  does  iron  buff  consist?    How  is  it  applied  to  cotton?     Give 
the  chemical  reaction  which  takes  place. 


THE  MINERAL  DYESTUFFS.  2$$ 

648.  Give  the  method  of  dyeing  iron  buff  by  using  chloride  of  lime.     Explain 
the  action  of  the  latter. 

649.  By  what  names  is  the  light  shade  of  iron  buff  known?     What  is  the 
general  fastness  of  iron  buff?    How  may  it  be  discharged? 

650.  What  dyes  may  be  topped  on  iron  buff  as  mordant?    What  is  the 
general  character  of  the  colors  obtained  ? 

651.  Of  what  does  iron  gray  consist?     How  is  it  applied  to  cotton?    What 
is  its  general  fastness  ? 

652 .  Of  what  does  manganese  brown  consist  ?     How  is  it  applied  to  cotton  ? 
By  what  other  name  is  it  known  ? 

653.  What  is  the  general  fastness  of  bistre?     How  may  bistre  be  dyed  with 
potassium  permanganate  ? 

654.  How  may  bistre  be  discharged  ?     How  is  Aniline  Black  dyed  on  bistre  ? 
How  may  bistre  be  made  fast  to  acid  ? 

655.  Of  what  use  is  bistre  in  indigo  dyeing?    How  is  bistre  employed  in 
imitating  fur  pelts?    How  may  bistre  be  dyed  on  wool? 

656.  Of  what  does  chrome  green  consist?    What  color  does  it  give?     How 
is  it  dyed  on  cotton  ?    What  is  its  general  fastness  ? 

657.  What  is  "khaki"?    How  is  it  dyed?    What  is  its  fastness?    How 
may  the  tone  of  the  color  be  varied  ? 

658.  Of  what  does  Prussian  blue  consist?     How  is  it  dyed  on  cotton?     By 
what  other  name  is  potassium  ferrocyanide  known  ? 

659.  How  is  Prussian  blue  dyed  on  wool?     How  may  the  blue  color  be 
developed  more  rapidly? 

660.  By  what  other  name  is  Prussian  blue  known?    What  dyestuff  has 
replaced  Prussian  blue  ? 

66 1.  For  what  is  Prussian  blue  used  in  silk  dyeing?    What  is  the  general 
fastness  of  Prussian  blue  ?     How  may  it  be  discharged  ? 

662.  What  is  the  function  of  stannous  chloride  in  dyeing  Prussian  blue? 
What  is  the  effect  of  boiling  soap  solutions  on  Prussian  blue  ? 

663.  What  is  the  theory  of  the  dyeing  of  Prussian  blue  on  wool?    What  is 
"blue  spirits "  ?     "Finishing  blue  spirits " ? 

664.  What  is  the  relative  importance  of  the  mineral  dyes  at  present  ?    How 
does  their  fastness  to  light,  etc.,  compare  with  coal-tar  dyes? 

665 .  What  is  the  general  theory  of  dyeing  mineral  colors  ?    In  what  branches 
of  dyeing  are  the  mineral  colors  still  used  ? 

666.  Name  some  of  the  minor  pigment  colors  which  may  be  dyed  on  cotton. 


SECTION  XXII. 
THE  VAT  DYES. 

Experiment   132.   Preparation  of  Indigo  Solution.  —  Mix   75 

grams  of  indigo  paste  (20  per  cent.)  with  40  cc.  of  hot  water,  and 
90  cc.  of  caustic  soda  solution  (42°  Tw.)  and  50  grams  of  hydro- 
sulphite  powder  (Blankit  T)  dissolved  in  200  cc.  of  water.  Stir 
gently  and  keep  the  temperature  at  about  no°F.  In  a  short 
time  the  liquor  should  be  of  a  clear  amber-yellow  color  with  a 
film  of  blue  on  the  top.  The  liquid  now  contains  indigo- 
white  and  serves  as  a  stock  indigo  solution  for  the  preparation  of 
the  dye-vat.  The  hydrosulphite  powder  (Blankit  T)  is  a  formalde- 
hyde compound  of  sodium  hydrosulphite  and  is  a  fairly  stable  body 
compared  with  most  hydrosulphite  derivatives.  It  is  a  strong 
reducing  agent  and  converts  the  indigo-blue  into  indigo-white. 
In  place  of  this  prepared  form  of  hydrosulphite  the  solution  of 
sodium  hydrosulphite  itself  may  be  used,  in  which  case  it  may  be 
prepared  as  follows:  130  grams  of  zinc  dust  are  made  into  a 
paste  with  55  cc.  of  water,  which  is  then  mixed  with  1000  cc.  of 
sodium  bisulphite  solution  of  72°  Tw.  As  the  mixture  is  liable 
to  become  heated,  the  temperature  should  be  kept  below  100°  F. 
by  the  addition  of  ice  or  cold  water;  when  the  chemical  action  has 
ceased,  dilute  to  2  litres  and  allow  to  stand  for  one  hour.  Then 
stir  in  200  cc.  of  a  20  per  cent,  milk-of-lime,  cold,  and  allow  to 
stand  for  2  hours.  This  causes  the  precipitation  of  all  the  zinc 
as  zinc  hydrate.  The  liquor  is  then  strained  to  free  it  from 
sediment,  and  preserved  in  a  closed  bottle.  The  hydrosulphite 
solution  thus  prepared,  if  kept  in  a  cool  place,  will  last  for  several 
weeks,  and  its  keeping  quality  will  be  enhanced  by  the  addition 
of  a  small  quantity  of  caustic  soda  solution.  When  zinc  dust 
reacts  with  a  solution  of  sodium  bisulphite  the  following  chemical 
change  takes  place: 

254 


THE   VAT  DYES.  2$$ 

Zn    +  3  NaHSO3  =  NaHSO2  +  Zn  (NaSO3)2  +  H2  O. 

Zinc     Sodium  bisulphite     Sodium  hydro-         Zinc-sodium  Water 

sulphite  'bisulphite 

Sodium  hydrosulphite  is  a  strong  reducing  agent,  being  itself 
oxidized  finally  to  sodium  bisulphate,  NaHSO4.  Its  use  forms 
a  very  convenient  means  for  the  preparation  of  dyeing  solutions 
of  indigo  as  well  as  the  other  vat  dyes.  The  sodium  hydrosul- 
phite solution  is  usually  prepared  by  the  dyer  as  a  stock  solution, 
and  used  as  occasion  requires  for  the  reduction  of  the  dyestuff 
to  be  added  to  the  vat. 

Experiment  133.  Dyeing  Indigo  with  Hydrosulphite  Vat.  — 
Prepare  the  dye- vat  as  follows:  to  one  litre  of  water  (70°  F.) 
add  2  grams  of  Blankit  T  (or  10  cc.  of  the  above  prepared  hydro- 
sulphite  liquor) ;  allow  to  stand  for  15  minutes,  then  run  in  100  cc. 
of  the  stock  indigo  solution  by  means  of  a  long-tubed  funnel. 
Stir  gently  and  allow  to  stand  for  30  minutes.  When  the  liquor 
is  clear  and  of  an  amber-yellow  color  it  is  ready  for  use.  Take 
a  test-skein  of  cotton  yarn  which  has  been  boiled  out  and  squeezed 
(but  not  dried)  and  pass  it  through  this  indigo  vat  without  heating. 
Take  care  to  manipulate  the  dyeing  so  as  to  disturb  the  liquor 
as  little  as  possible,  as  much  exposure  to  the  air  will  cause  undue 
oxidation  and  considerable  indigo  will  be  precipitated  in  the 
vat.  When  the  skein  has  become  thoroughly  and  evenly  satu- 
rated with  the  liquor,  squeeze  it  out  well,  and  then  expose  the 
skein  to  the  air  for  5  or  10  minutes.  When  the  skein  first  comes 
from  the  vat  it  should  be  of  a  yellowish  green  color;  on  exposure 
to  the  air  it  soon  turns  blue.  The  dyed  skein  is  then  washed 
well  in  water  and  afterwards  in  a  warm  soap  solution  in  order  to 
remove  all  alkali  and  unfixed  dyestuff  (420).  Dye  a  second 
test-skein  of  cotton  yarn  in  a  similar  manner,  but  after  oxidizing 
in  the  air  give  it  a  second  passage  through  the  indigo  vat  and 
oxidize  again,  after  which  wash  and  soap.  This  will  represent 
the  color  obtained  by  two  dips  (421).  In  the  same  manner 
dye  a  third  skein,  giving  it  four  dips  (422).  Also  dye  skeins  of 
woolen  yarn  in  the  same  manner,  giving  one  dip  (423),  two 
dips  (424)  and  four  dips  (425).  For  the  woolen  yarn  use  a 


256  DYEING   AND    TEXTILE   CHEMISTRY. 

first  wash  water  acidulated  with  a  little  sulphuric  acid  in  order 
to  neutralize  the  alkali;  then  wash  well  again  in  plain  water  and 
finally  soap.  If  the  dye-vat  turns  bluish  owing  to  oxidation  a  fresh 
quantity  of  hydrosulphite  must  be  added,  the  liquor  stirred  gently 
and  allowed  to  stand  for  15  minutes.  To  maintain  the  proper 
dyeing  strength  of  the  vat  fresh  additions  of  the  stock  solution 
of  indigo  are  made  from  time  to  time  as  needed.  If  too  much 
hydrosulphite  is  present  in  the  vat  the  color  will  not  be  well  taken 
up  and  the  blue  will  not  develop  quickly  on  exposure  to  the  air. 

The  hydrosulphite  vat  for  indigo  is  the  simplest  and  the  most 
popular  method  of  applying  this  dyestuff  at  the  present  time. 
Other  forms  of  vats,  depending  on  the  nature  of  the  reducing 
agent,  have  been  used.  The  fermentation  vat  is  the  oldest  form 
of  indigo  dyeing  and  is  still  used  to  a  considerable  extent  in  wool 
dyeing.  Its  operation  depends  on  the  reducing  action  of  certain 
ferments,  and  it  is  prepared  with  bran,  woad,  and  madder.  The 
woad  is  supposed  to  furnish  the  particular  ferment,  while  the 
bran  and  madder  serve  as  nourishment  for  the  growth  of  the  fer- 
ment. The  alkali  employed  is  lime,  which  serves  the  double 
purpose  of  neutralizing  the  acid  liberated  in  the  fermentation 
and  providing  the  alkali  necessary  for  the  solution  of  the 
reduced  indigo.  The  fermentation  vat  is  difficult  to  prepare  and 
also  difficult  to  maintain  in  proper  working  condition.  The 
copperas  vat  employs  ferrous  sulphate  as  the  reducing  agent  and 
lime  as  the  alkali.  It  is  a  cumbersome  and  unsatisfactory 
method  and  is  not  used  at  present.  The  zinc  vat  uses  zinc  dust 
for  the  reducing  agent  and  either  lime  or  caustic  soda  as  the 
alkali.  It  is  quite  an  efficient  form  of  vat  and  is  still  employed 
considerably  in  cotton  dyeing.  All  of  these  vats,  however,  con- 
tain a  large  amount  of  sediment,  and  care  must  be  taken  in 
dyeing  not  to  disturb  this  sediment  or  it  will  get  into  the  goods 
being  dyed.  There  is  also  considerable  loss  of  indigo  in  these 
vats,  whereas  in  the  hydrosulphite  vat  there  is  no  sediment,  and 
the  loss  of  indigo  is  exceedingly  small. 

Test  the   fastness  of  the   indigo   dyeings   to   light,   washing, 
fulling,  acids,  and  chloring  (on  cotton). 


THE   VAT  DYES. 

Experiment  134.  Use  of  Thio-Indigo  Red.  —  Stir  50  grams  of 
Thio-Indigo  Red  B  paste  with  200  cc.  of  water,  add  10  cc.  of  caustic 
soda  solution  of  76°  Tw.,  then  gradually  stir  in  10  grams  hydro- 
sulphite  powder  (Blankit  T).  Heat  to  i2o°F.  and  allow  to 
stand  for  2  hours,  or  until  the  reduction  is  complete  and  the 
solution  is  of  a  yellow  color.  Dilute  to  one  litre  and  preserve 
as  a  stock  solution  for  dyeing.  For  the  dye-vat  take  400  cc.  of 
water  of  a  temperature  of  about  100°  F.,  add  20  grams  of  salt,  a 
small  quantity  (o.i  gram)  of  hydrosulphite  powder  and  a  few 
drops  of  caustic  soda  solution  (76°  Tw.).  Stir  well,  allow  to 
stand  for  15  minutes  and  then  add  100  cc.  of  the  stock  dye-solu- 
tion. Stir  gently  and  allow  to  stand  for  one  hour,  when  the  vat 
should  be  of  a  clear  yellow  color  and  ready  for  dyeing.  Steep  a 
test-skein  of  cotton  yarn  in  this  vat  for  15  minutes,  then  squeeze 
and  oxidize  in  the  air  for  30  minutes  (426).  Dye  another  skein 
in  the  same  manner,  giving  it  three  dips  (427),  and  a  third 
skein,  giving  it  five  dips  (428).  The  addition  of  salt  is  for 
the  purpose  of  causing  a  more  rapid  fixation  and  better  exhaus- 
tion of  the  dyestuff.  The  bath  may  be  strengthened  by  further 
additions  of  the  stock  solution.  If  the  bath  becomes  red  and  loses 
its  clear  yellow  color  a  little  more  hydrosulphite  powder  should 
be  added,  and  the  liquor  stirred  gently  and  allowed  to  stand  for 
15  to  30  minutes  to  allow  it  to  become  thoroughly  reduced  again. 

Prepare  a  vat  with  Thio-Indigo  Scarlet  R  in  the  same  manner 
as  above  and  make  dyeings  with  one  dip  (429),  three  dips  (430), 
and  five  dips  (431). 

When  the  dyeings  have  been  exposed  to  the  air  sufficiently  to 
become  thoroughly  oxidized,  they  should  be  well  washed  in  water 
and  then  in  warm  soap  solution  to  remove  all  unfixed  dyestuff 
and  chemicals. 

Test  the  fastness  of  the  two  dyestuffs  to  light,  washing,  and 
bleaching. 

Experiment  135.  Use  of  Indanthrene  Blue.  —  Prepare  a 
dye-bath  with  400  cc.  of  water,  8  cc.  of  caustic  soda  solution 
(53°  Tw.),  and  8  grams  of  Blankit  T.  Heat  to  120°  F.,  and  then 
stir  in  2  grams  (20  per  cent.)  of  Indanthrene  Blue  GCD.  When 


258  DYEING   AND    TEXTILE   CHEMISTRY. 

the  liquor  is  clear  and  shows  no  undissolved  particles  (test  by 
dropping  on  a  piece  of  filter  paper) ,  the  bath  is  ready  for  dyeing. 
Dye  a  test-skein  of  cotton  yarn  in  this  bath  for  one  hour  at  120°  F. 
Keep  the  cotton  beneath  the  liquor  and  expose  the  bath  as  little 
as  possible  to  the  action  of  the  air.  After  dyeing  rinse  well  in 
water,  then  in  water  slightly  acidulated  with  sulphuric  acid,  and 
finally  in  a  dilute  soap  bath  (432).  Test  the  fastness  of  this 
color  to  light,  washing,  and  bleaching. 

The  indanthrene  colors  are  best  applied  in  mechanical  dyeing 
apparatus  so  that  the  liquor  during  circulation  comes  into 
contact  with  the  air  as  little  as  possible.  The  indanthrene 
dyestuffs  are  somewhat  different  in  their  behavior  than  the 
indigo  dyes,  as  they  exhaust  very  well  from  the  bath  and  the 
color  dyes  up  directly  on  the  fibre  and  does  not  require  a  sub- 
sequent oxidation.  On  this  account  the  amount  of  coloring- 
matter  to  be  used  may  be  based  directly  on  a  percentage  of 
the  material  dyed. 

Experiment  136.  Use  of  Indanthrene  Yellow.  —  Prepare  a 
dye-bath  as  above,  using  10  per  cent,  of  Indanthrene  Yellow  G, 
and  dye  a  test-skein  of  cotton  yarn  for  one  hour  at  a  temperature 
of  140°  F.  It  will  be  noticed  that  this  dyestuff  on  reduction  gives 
a  blue  solution  and  that  the  cotton  is  blue  in  color  when  first 
taken  from  the  dye-bath.  For  the  better  development  of  this 
color,  after  dyeing,  squeeze,  rinse  in  water,  and  then  pass  through 
a  very  dilute  cold  solution  of  chrome  (o.i  gram  per  litre).  This 
facilitates  the  oxidation  of  the  color  very  materially.  Finally 
wash  well  and  soap  as  usual  (433).  Test  this  color  for  fastness 
to  light,  washing,  and  bleaching. 

Experiment  137.  Production  of  Fast  Pink  with  Indanthrene 
Dyes.  —  Prepare  a  dye-bath  as  in  Exp.  135,  using  3  per  cent, 
of  Indanthrene  Red  B,  and  dye  a  test-skein  of  cotton  yarn  for 
one  hour  at  140°  F.  Wash  well  and  rinse  in  dilute  acid,  and 
finally  soap  (434) .  This  color  gives  a  rather  bright  pink  when  used 
in  small  percentages  and  the  color  is  very  fast  to  light,  washing, 
acids,  and  bleaching.  By  combining  with  small  amounts  of 
Indanthrene  Yellow  R,  bright  yellowish  pinks  may  be  obtained. 


THE   VAT  DYES.  259 

Experiment  138.  Use  of  Ciba  Blue.  —  Prepare  the  dye- vat  as 
follows:  Make  a  paste  with  0.5  gram  of  Ciba  Blue  2B  (powder), 
i  cc.  caustic  soda  (76°  Tw.)  solution,  and  some  hot  water;  also 
dissolve  2  grams  of  hydrosulphite  powder  (Blankit  T)  in  15  cc. 
of  cold  water  and  i  cc.  of  caustic  soda  solution.  Then  add  this 
hydrosulphite  solution  to  the  dyestuff,  dilute  to  400  cc.  with  hot 
water  and  slowly  boil.  The  dye-vat  should  then  be  completely 
reduced  and  be  of  a  golden  yellow  color.  Dye  a  test-skein  of 
cotton  yarn  in  this  bath  for  30  minutes  at  170°  F.,  squeeze  well, 
and  allow  to  oxidize  in  the  air  for  15  minutes;  then  rinse  well  in 
cold  water,  and  finally  work  in  a  boiling  dilute  soap  bath  (435). 
The  treatment  with  the  boiling  soap  bath  very  materially  brightens 
the  color,  and  also  gives  it  greater  fastness  to  washing  and 
bleaching.  A  still  greater  fastness  to  bleaching  may  be  obtained 
by  an  after-treatment  with  bluestone  in  the  usual  manner. 

NOTES. 

i.  Classes  of  Vat  Dyes.  —  The  vat  dyes  include  indigo, 
thio-indigo  dyes,  indanthrene  dyes,  ciba  dyes,  and  algol  dyes. 
With  the  exception  of  indigo  they  are  all  of  comparatively  recent 
introduction.  The  dyestuffs  themselves  are  insoluble  in  water  but 
when  reduced  they  yield  products  which  are  soluble  in  alkalies. 
Therefore  the  dye-bath  consists  of  a  mixture  of  the  dyestufl, 
a  strong  reducing  agent,  and  an  alkali  solution;  such  a  mixture 
is  termed  a  vat.  Indigo  is  a  blue  dyestuff;  the  thio-indigo  dyes 
include  a  purplish  red  and  a  scarlet;  the  indanthrene  dyes  com- 
prise blue,  violet,  gray,  yellow,  brown,  green,  and  dull  red  color- 
ing-matters; among  the  ciba  dyes  are  to  be  found  blue,  violet 
and  red  colors,  as  also  among  the  algol  dyes.  The  vat  dyes  are  in 
general  characterized  by  great  fastness  to  light,  washing,  acids, 
alkalies,  and  in  some  cases  to  bleaching  with  chloride  of  lime. 
This  makes  them  very  valuable  products,  but  at  the  present 
time,  with  the  exception  of  indigo,  they  are  very  expensive.  The 
vat  dyes  may  be  applied  to  all  fibres,  but  they  are  probably  more 
suited  to  the  dyeing  of  cotton  on  account  of  the  alkaline  nature 
of  the  dye-vat.  The  material  to  be  dyed  is  simply  immersed  in 


260  DYEING  AND    TEXTILE  CHEMISTRY. 

the  dye-bath  or  vat  until  thoroughly  impregnated  with  the  solu- 
tion; it  is  then  squeezed  and  exposed  to  the  air,  which  causes  the 
oxidation  of  the  reduced  "  leuco  "  compound  and  the  formation 
of  the  color.  The  temperature  of  the  vat  is  usually  lukewarm 
for  the  purpose  of  facilitating  the  impregnation  of  the  fibre  with 
the  solution.  In  some  cases  the  dipping  and  oxidation  have  to 
be  repeated  several  times  in  building  up  a  heavy  color. 

2.  Indigo.  —  This  is  one  of  the  oldest  dyestuffs  of  which  we 
have  any  knowledge,  and  even  at  the  present  time  it  is  perhaps 
the  most  important  and  extensively  used  of  all  dyes.  Up  to 
within  rather  recent  years  indigo  was  obtained  from  the  indigo 
plant  extensively  cultivated  in  India  and  other  Asiatic  countries, 
as  well  as  the  tropical  countries  of  Central  and  South  America. 
Previous  to  the  introduction  of  the  oriental  indigo  (about 
1500  A.D.)  into  Europe,  the  same  dye  had  been  extracted  from 
a  plant  known  as  woad  (I satis  tinctoria).  The  indigo  plant  is 
botanically  known  as  Indigofera,  and  there  are  several  species, 
the  more  important  of  which  are  /.  tinctoria,  I.  anil,  I.  disperma, 
and  /.  argentea.  Woad  is  still  used  to  some  extent  in  the  prepara- 
tion of  certain  vats,  but  only  in  connection  with  indigo,  and 
never  by  itself.  The  coloring  principle  present  in  the  indigo 
plant  is  known  as  indigotin,  or  indigo  blue.  The  crude  product, 
however,  contains  several  other  substances  in  varying  amounts, 
such  as  indirubin  or  indigo-red,  indigo-brown,  indigo-glutin, 
and  some  mineral  matters.  The  process  of  extracting  indigo 
from  the  plant  is  rather  complicated.  The  plant  is  cut  when 
ripened,  the  leaves  are  stripped  off  and  steeped  for  some  time  in 
vats  of  water.  By  a  process  of  fermentation  the  coloring-matter 
which  exists  in  the  plant  as  a  glucoside  (indican)  is  changed  to  a 
soluble  form  and  dissolves  in  the  water,  yielding  an  olive  green 
solution.  ,  The  liquor  is  run  off  into  another  vat,  where  it  is 
beaten  or  churned  up  so  as  to  expose  it  to  the  oxidizing  action  of 
the  air.  This  causes  the  precipitation  of  the  insoluble  indigo- 
tin  as  a  fine  blue  mud.  This  is  collected,  dried,  and  pressed 
into  small  bricks  or  cubes  about  three  inches  in  size,  in  which 
form  it  appears  in  trade.  At  the  present  time  indigo  is  also 


THE    VAT  DYES.  26  1 

prepared  in  large  quantities  from  coal-tar  products  by  synthetic 
processes.  There  are  several  methods  employed;  the  principal 
one  uses  naphthalene  as  the  starting  point.  The  synthetic 
indigo  is  rapidly  replacing  the  natural  product,  as  it  can  be  made 
cheaper,  purer,  and  more  uniform.  Chemically  it  is  identically 
the  same  as  the  indigo  derived  from  the  plant.  Indigo  is  exten- 
sively used  for  both  wool  and  cotton  dyeing,  though  it  is  being 
used  proportionately  less  for  the  dyeing  of  wool  since  the  intro- 
duction of  the  fast  alizarin  and  anthracene  blue  dyes.  It  is 
not  much  employed  for  the  dyeing  of  silk.  In  calico  print- 
ing it  has  an  extensive  application,  principally  for  discharge 
styles. 

The  chemical  formula  of  indigo  is  rather  complicated,  but  it 
has  been  definitely  established  as 

/co\    _r/co\ 

^e  n4  \         /  V  !  *  v  s^         /  ^6  n4. 


In  preparing  the  vat  this  indigotin  is  reduced  to  a  leuco  (or 
colorless)  compound  called  indigo-white,  which  is  readily  soluble 
in  alkalies  (solutions  of  caustic  soda,  soda  ash,  lime,  etc.).  In 
this  form  it  is  readily  absorbed  by  the  fibre,  in  which  it  is 
oxidized  again  to  indigotin  (or  indigo-blue)  by  the  action  of 
the  air. 

3.  Thio-Indigo  Dyes.  —  These  are  synthetic  dyestuffs  closely 
related  to  indigo  hi  chemical  composition  and,  as  the  name  would 
indicate,  containing  sulphur.  These  dyes  are  of  very  recent  dis- 
covery and  comprise  two  commercial  products,  Thio-Indigo  Red  B 
and  Thio-Indigo  Scarlet  R.  The  chemical  formula  for  the  red 
dye  has  been  determined  as 


-6        4  \      S      /  ~          \      S      /       6         *> 

from  which  its  relation  to  indigo  may  be  readily  seen.  These 
dyes  come  into  the  market  in  the  form  of  pastes  containing  20  per 
cent,  of  coloring-matter,  and  are  dyed  in  vats  prepared  about  in 
the  same  manner  as  for  indigo.  Thio-Indigo  Red  is  also  soluble 


262  DYEING   AND    TEXTILE   CHEMISTRY. 

in  sodium  sulphide  with  reduction,  and  hence  may  be  used  in 
practically  the  same  manner  as  a  sulphur  dye,  but  the  color  so 
obtained  is  not  as  satisfactory  as  when  produced  from  the  vat. 

4.  The  Indanthrene  Dyes.  —  These  dyes  are  not  derivatives  of 
indigo,  but  are  prepared  from  amido-anthraquinone  compounds. 
They  include  quite  a  range  of  colors  at  the  present  time  and  are 
being  constantly  added  to,  though  a  bright  red  and  green  have 
not  yet  been  found.     The  list  at  the  present  time  includes: 

Indanthrene  Blue  GCD. 

Indanthrene  Blue  RS,  RC,  RSP,  RZ,  and  RRZ. 

Indanthrene  Violet  RT,  R  extra. 

Indanthrene  Dark  Blue  B,  BB,  and  BO. 

Indanthrene  Maroon  R. 

Indanthrene  Gray  B. 

Indanthrene  Yellow  G  and  R. 

Indanthrene  Orange. 

Indanthrene  Green. 

Indanthrene  Copper. 

Indanthrene  Brown  B. 

Indanthrene  Red  B. 

Indanthrene  Olive  G. 

These  dyes  are  brought  into  solution  in  caustic  soda  by  reduc- 
tion with  sodium  hydrosulphite.  In  a  vat  thus  prepared,  how- 
ever, they  act  very  much  after  the  manner  of  substantive  dyes  on 
cotton,  some  of  them  being  dyed  almost  at  the  boil,  the  dyeing 
and  development  of  the  color  taking  place  almost  simultaneously, 
and  the  dye-bath  becoming  practically  exhausted.  Some  of 
these  dyes,  however,  must  be  applied  at  lower  temperatures, 
and  require  subsequent  oxidation  in  order  to  develop  the  color. 
The  indanthrene  dyes  are  brought  into  trade  in  the  form  of 
pastes  containing  20  per  cent,  of  coloring-matter.  For  the 
production  of  heavy  shades  large  proportions  of  the  pastes  must 
be  taken. 

5.  The  Ciba  Dyes.  —  These  are  halogen  derivatives  of  indigo 
and  are  applied  in  the  same  general  manner.     The  blue  dyes  of 
this  series  are  the  most  important,  and  possess  excellent  fastness 
to  light,  washing,  and  bleaching  with  chloride  of  lime. 


THE   VAT  DYES.  263 

SAMPLES. 

420.  Indigo  on  cotton;  one  dip. 

421.  Indigo  on  cotton;  two  dips. 

422.  Indigo  on  cotton;  four  dips. 

423.  Indigo  on  wool;  one  dip. 

424.  Indigo  on  wool;  two  dips. 

425.  Indigo  on  wool;  four  dips. 

426.  Thio-Indigo  Red  on  cotton;  one  dip. 

427.  Thio-Indigo  Red  on  cotton;  three  dips. 

428.  Thio-Indigo  Red  on  cotton;  five  dips. 

429.  Thio-Indigo  Scarlet  R  on  cotton;  one  dip. 

430.  Thio-Indigo  Scarlet  R  on  cotton;  three  dips. 

431.  Thio-Indigo  Scarlet  R  on  cotton;  five  dips. 

432.  Indanthrene  Blue  GCD  on  cotton. 

433.  Indanthrene  Yellow  G  on  cotton. 

434.  Indanthrene  Red  B  on  cotton. 
435-    Ciba  Blue  on  cotton. 

QUIZ  22. 

667.  What  is  meant  by  a  "vat"  dye ?     How  does  this  class  in  general  differ 
from  other  classes  of  dyestuffs  ? 

668.  Name  the  principal  members  belonging  to  the  group  of  vat  dyes. 
What  range  of  color  can  be  obtained  with  these  dyes? 

669.  What  is  the  general  principle  of  applying  the  vat  dyes?    What  fibres 
are  mostly  dyed  with  these  colors? 

670.  What  are  the  general  characteristics  of  the  vat  dyes  as  to  fastness? 
What  is  the  chief  drawback  in  the  general  use  ? 

671.  What  is  meant  by  a  "leuco"  compound?    Why  do  the  vat  dyes  in 
general  require  to  be  oxidized  ? 

672.  In  dyeing  with  vat  colors,  how  are  heavy  shades  generally  built  up? 
Does  the  dye-bath  with  vat  colors  usually  exhaust  well  ? 

673.  What  is  "hydrosulphite"?    Name  some  of  the  commercial  prepara- 
tions of  this  substance.     What  is  its  chemical  function  ? 

674.  How  is  a  solution  of  sodium  hydrosulphite  prepared?      Give  the 
chemical  reaction  which  takes  place.     Is  this  solution  stable  ? 

675.  Give  some  historical  information  concerning  indigo.     What  was  its 
source  in  former  years,  and  what  is  its  chief  source  at  the  present  time  ? 

676.  How  is  indigo  obtained  from  the  plant?    What  is  the  coloring  prin- 
ciple of  indigo  ?    What  other  substances  exist  in  natural  indigo  ? 

677.  What  is  the  chemical  formula  of  indigo?    What  is  indican;  indigo- 
white  ? 

678.  Give  an  outline  of  the  general  method  of  preparing  the  indigo  vat  with 
hydrosulphite. 


264  DYEING  AND    TEXTILE  CHEMISTRY. 

679.  Give  the  general  method  of  dyeing  cotton  and  wool  in  the  indigo  vat. 
What  temperatures  are  employed,  and  how  is  the  material  treated  after  dyeing? 

680.  What  other  forms  of  vat  are  employed  for  the  dyeing  of  indigo  ?     Give 
the  reducing  agents  and  the  alkalies  used. 

68 1.  What  can  you  say  regarding  the  fastness  of  indigo  blues  to  light, 
washing,  acids,  and  bleaching  ? 

682.  What  is  Thio-Indigo  Red?    How  is  it  applied  in  dyeing?    What  are 
its  drawbacks  as  a  dyestuff  ?    What  is  its  general  fastness  ? 

683.  Name  some  of  the  indanthrene  series  of  dyes.     How  are  they  applied 
in  dyeing  ?    What  amounts  of  dyestuff  are  necessary  to  yield  full  shades  ? 

684.  How  does  the  fastness  of  Indanthrene  Blue  compare  with  that  of 
indigo  ? 

685.  How  may  a  pink  fast  to  washing  and  bleaching  be  obtained  on  cotton 
with  indanthrene  dyes? 

686.  What  are  the  ciba  dyes?     Give  the  method  of    their  application. 
How  does  Ciba  Blue  compare  with  Indanthrene  Blue? 


SECTION  XXIII. 

THE  TESTING  OF  DYESTUFFS. 

Experiment  139.  To  Obtain  the  Money  Value  of  a  Dyestuff 
Sample.  —  In  the  testing  of  a  dyestuff  sample  for  its  money  value 
it  is,  of  course,  necessary  to  test  it  in  comparison  with  another 
sample  of  the  same  (or  a  strictly  similar)  dyestuff  of  a  known  or 
established  money  value.  Take  two  samples  of  Wool  Blue  and 
prepare  solutions  of  the  same  containing  2.5  grams  per  litre, 
labelling  them  "A"  and  "B."  Prepare  two  dye-baths  con- 
taining the  same  amount  of  water,  acid,  and  glaubersalt,  and 
add  10  cc.  of  the  respective  dyestuff  solutions.  Then  dye  two 
test-skeins  of  woolen  yarn  identical  in  character  and  weight  in 
these  baths,  maintaining  carefully  the  same  conditions  as  to 
temperature  and  time  of  dyeing  in  both  cases.  After  dyeing  in 
the  usual  manner  for  45  minutes,  remove  the  two  skeins,  squeeze 
the  excess  of  liquor  back  into  the  respective  dye-baths,  and  then 
dry  up  portions  of  the  two  skeins.  Now  compare  these  for  depth 
of  color  and  set  aside  the  heavier  shade  for  comparison ;  continue 
dyeing  the  weaker  shade,  adding  to  the  dye-bath  sufficient  of  its 
respective  color  to  bring  the  shade  to  a  match  with  the  other 
sample.  The  amounts  of  the  two  dyestuff  solutions  used  to 
produce  the  same  depth  of  shade  will  be  inversely  proportional  to 
the  values  of  the  respective  dyes,  so  if  the  actual  money  value  of 
one  of  the  samples  is  known  it  is  a  simple  matter  to  calculate  the 
relative  value  of  the  second.  For  example,  suppose  that  on  the 
first  dyeing,  sample  "A"  proved  to  be  strongest  dyestuff;  on 
continuing' the  dyeing  of  "B,"  it  was  necessary  to  use  2.5  cc. 
more  dye  solution  to  match  "A";  further,  suppose  that  sample 
"A"  was  priced  at  42  cents  per  pound.  What  would  be  the 
relative  money  value  of  "B"? 

Dye  solution  used  for  " A,"      10     cc. 

Dye  solution  used  for  "B,"      12.5  cc. 

265 


266  DYEING  AND    TEXTILE  CHEMISTRY. 

Then      12.5  :  10  =  42  :  x 

10  X  42 
and  x  =  -  -  =  33.6  cents  per  pound. 

This  method  of  testing  the  comparative  strength  or  value  of 
dyestuffs  may  be  carried  to  a  rather  high  degree  of  accuracy,  but 
it  is  necessary  that  the  comparative  dye-tests  be  made  under 
exactly  the  same  conditions  in  every  respect,  and  also  that  the 
eye  be  trained  to  match  the  depth  of  colors  with  great  accuracy. 
The  amounts  of  the  dye  solutions  should  be  accurately  measured 
by  means  of  a  graduated  pipette,  and  exactly  the  same  amounts 
of  sulphuric  acid  and  glaubersalt  should  also  be  taken  by 
means  of  definitely  measured  solutions;  and  further  the  total 
volume  of  each  dye-bath  should  be  the  same.  To  insure  the 
most  accurate  results,  it  is  best  to  carry  out  a  second  dyeing  of 
the  weaker  sample,  using  the  required  amount  of  its  solution 
added  to  the  bath  all  at  one  time.  This  is  especially  desirable 
if  the  second  sample  has  been  brought  to  a  match  by  a  number 
of  successive  additions  of  the  color  solution.  For  instance,  in 
the  example  quoted  above,  suppose  the  several  additions  of  the 
color  solution  of  "B"  to  have  been  as  follows: 

First,    10     cc.  Fourth,  0.5  cc. 

Second,  i     cc.  Fifth,     0.3  cc. 

Third,    0.5  cc.  Sixth,     0.2  cc. 

making  in  all  12.5  cc.  It  would  be  better  to  then  dye  another 
skein,  using  12.5  cc.  as  a  first  addition  to  the  dye-bath.  It  will 
frequently  be  found  that  a  slightly  increased  amount  of  the  dye 
solution  will  be  required  to  bring  this  second  test  to  a  match. 
This  is  accounted  for  by  the  fact  that  the  prolonged  dyeing 
necessitated  by  the  numerous  additions  to  the  bath  will  cause  an 
abnormal  absorption  of  dyestuff. 

If  properly  carried  out,  this  method  of  analysis  is  capable  of 
giving  results  accurate  to  within  at  least  two  per  cent.,  provided 
the  samples  being  tested  are  the  same  kind  of  dyestuff.  If, 
however,  the  dyes  are  not  quite  of  the  same  tone  of  color,  some 
difficulty  may  be  experienced  in  judging  accurately  the  point 


THE   TESTING  OF  DYESTUFFS.  267 

at  which  the  samples  are  matched  and  considerable  skill  in 
matching  will  be  required  to  arrive  at  their  proper  valuation. 
The  matching  in  this  case  may  be  usually  rendered  somewhat 
easier  by  observing  the  colors  through  red,  blue  or  yellow  glasses, 
which  have  the  effect  of  cutting  out  certain  undesirable  tones. 
Furthermore,  the  eye  is  more  sensitive  to  differences  in  intensity 
of  some  colors  than  in  others;  for  instance,  it  is  quite  difficult 
to  detect  small  differences  in  the  depth  of  yellow  colors,  whereas 
in  blues  or  reds,  small  differences  are  easily  detected.  Violet 
colors  and  reddish  tones  of  blue  are  also  rather  difficult  to 
accurately  match;  and  dull  and  broken  ton'es  of  any  color  are 
harder  to  approximate  than  clear  and  bright  tones.  It  is  not 
well  to  employ  too  heavy  shades  for  comparison,  or  the  accuracy 
of  the  method  will  be  much  impaired. 

As  sometimes  one  dyestuff  may  exhaust  better  in  the  first 
bath  than  another  corresponding  dye,  or  even  with  the  same 
dyestuff,  it  is  at  times  possible  to  mix  with  it  some  chemical 
to  cause  it  to  exhaust  better  than  when  pure,  in  the  practical 
testing  of  dyes  it  is  best  to  make  an  exhaust  test.  This  is  done  by 
diluting  the  dye-bath  used  for  the  first  dyeing  to  its  original 
volume,  and  without  the  further  addition  of  dyestuff  or  reagents, 
to  dye  a  second  test-skein.  The  intensity  of  the  dyeing  thus 
obtained  will  measure  the  degree  of  exhaustion  of  the  dyestuff  in 
the  first  bath. 

It  is  not  well  to  employ  too  heavy  shades  for  comparison;  as  a 
rule,  from  one-half  to  one  per  cent,  dyeings  will  be  found  quite 
satisfactory  for  most  colors.  In  the  case  of  black  dyes,  however, 
where  it  is  necessary  to  obtain  a  comparison  of  the  tone  of  black 
produced,  it  will,  of  course,  be  necessary  to  use  more  than  one 
per  cent,  of  dyestuff. 

In  cases  where  the  test-skeins  must  be  mordanted  or  otherwise 
treated  before  or  after  the  dyeing,  care  must  be  taken  that  the 
several  skeins  employed  in  the  tests  receive  exactly  the  same 
manner  and  degree  of  treatment.  In  order  to  insure  the 
proper  conditions  it  is  best  to  mordant  all  the  test-skeins 
used  simultaneously  and  together  in  the  same  bath;  and 


268  DYEING   AND    TEXTILE   CHEMISTRY. 

this    should  also    be    done  where    any    after-treatment    of    the 
dyeing  is  required. 

Make  a  comparative  test  of  two  samples  of  a  substantive 
cotton  color;  two  samples  of  a  basic  color  for  cotton,  mordanting 
with  tannin-antimony;  two  samples  of  an  alizarin  color  for  wool 
on  a  chrome  mordant;  and  two  samples  of  an  anthracene  color 
for  wool,  after-mordanting  with  chrome.  In  all  these  cases  make 
exhaust  tests  on  the  same  dye-bath. 

Experiment  140.  To  Determine  if  a  Dyestuff  is  Simple  or 
Mixed.  —  A  large  number  of  the  dyestuffs  on  the  market  are 
not  simple  or  single  coloring-matters,  but  consist  of  two  or  more 
dyestuffs  mixed  together.  This  mixing  of  colors  is  practised 
for  the  purpose  of  altering  the  tone  of  the  dyestuff;  or  for  the 
forming  of  various  colors,  such  as  the  production  of  a  green  by 
mixing  a  blue  and  a  yellow  dye.  It  is  also  practised  for  the 
purpose  of  adulterating  various  dyes  with  others  of  cheaper 
quality. 

The  presence  of  mixtures  in  a  dyestuff,  however,  must  not 
always  be  taken  as  evidence  of  sophistication.  In  the  manu- 
facture of  dyestuffs  it  often  happens  that  successive  lots  of  the 
same  coloring-matter  do  not  exhibit  precisely  the  same  tone, 
but  it  is  very  desirable  to  the  dyer  that  the  dyestuff  as  sold  should 
always  be  of  exactly  the  same  tone.  The  manufacturer,  there- 
fore, adopts  a  standard,  and  tones  the  various  lots  to  match 
this  standard  by  the  proper  addition  of  suitable  but  similar 
dyes.  Therefore  a  dyestuff  may  be  a  perfectly  true  article  and 
yet  show  evidence  of  mixed  colors.  The  amount  of  mixture,  how- 
ever, under  these  circumstances  is  very  small;  whereas  admixture 
for  purposes  of  sophistication  is  usually  rather  large. 

A  simple  test  of  considerable  practical  value  for  detecting  a 
mixture  of  dyes  is  as  follows:  Moisten  a  small  sheet  of  paper 
with  water,  place  a  little  of  the  dyestuff  on  one  end  of  the  paper 
and  then  blow  the  breath  across  it  so  as  to  scatter  the  dyestuff 
in  fine  particles  over  the  paper.  A  mixture  of  dyes  will  generally 
give  a  mottled  appearance  of  several  colors.  A  modification  of 
this  test,  which  at  times  will  yield  better  results,  is  to  place  some 


THE   TESTING  OF  DYESTUFFS.  269 

concentrated  sulphuric  acid  in  a  porcelain  dish,  and  then  sprinkle 
a  little  of  the  suspected  dyestuff  over  the  surface  of  the  acid.  If 
particles  of  different  dyes  (even  though  they  may  be  of  the  same 
color  originally)  are  present  they  will  generally  show  different 
colors  on  contact  with  the  acid,  causing  them  to  be  easily  detected. 
Prepare  a  green  dyestuff  by  making  an  intimate  mixture  of  one 
part  Naphthol  Yellow  and  three  parts  Wool  Blue,  and  test  the 
mixture  so  obtained  by  the  two  methods  just  given. 

A  further  method  of  testing  depends  on  the  difference  in  the 
capillarities  of  the  two  dyestuffs  when  in  solution.  A  portion  of 
the  suspected  dyestuff  is  dissolved  in  water  and  a  single  drop  of 
the  solution  placed  on  a  piece  of  filter  (or  blotting)  paper.  If 
the  dyestuff  is  a  mixture,  two  rings  of  color  will  generally  be 
observed  as  the  drop  of  solution  spreads  out  over  the  paper. 
Test  the  green  mixed  dyestuff,  as  prepared  above,  in  this  manner, 
and  observe  the  result.  Sometimes  this  test  may  be  rendered 
more  distinct  by  using  an  alcoholic  solution  of  the  dyestuff. 
Make  this  test  with  a  drop  from  an  alcoholic  solution  of  a  mixture 
of  Methyl  Violet  and  Safranine. 

Experiment  141.  To  Determine  the  Class  to  which  a  Dyestuff 
Belongs.  —  It  is  often  desirable  to  ascertain  the  chemical  char- 
acter of  a  sample  of  unknown  dyestuff;  that  is  to  say,  the  classifi- 
cation of  a  coloring-matter  with  reference  to  its  dyeing  properties. 
With  reference  to  these  properties,  nearly  all  dyes  may  be  classified 
into  four  general  groups,  as  follows: 

(a)  Acid  dyes,  including  those  that  are  dyed  in  an  acid  bath, 
and  which  consist  of  the  salts  of  color  acids. 

(b)  Basic  dyes,  including  those  that  are  dyed  in  neutral  or 
alkaline  baths,  and  which  consist  of  the  salts  of  color  bases. 

(c)  Substantive  dyes,  including  those  that  dye  both  animal 
and  vegetable  fibres,  and  which  consist  principally  of  benzidine 
and  allied  derivatives. 

(d)  Mordant  dyes,  including  those  that  do  not  dye  either  the 
animal  or  vegetable  fibres  directly,  but  which  form  color-lakes 
with   various   metallic   oxides.     These   dyes   consist   mostly   of 
anthracene  derivatives   and   allied  compounds  of  an   alcoholic 


2/0  DYEING  AND    TEXTILE  CHEMISTRY. 

nature.  This  classification,  however,  must  not  be  taken  as 
absolute  and  rigid,  as  one  class  may  merge  into  another  in  almost 
an  imperceptible  manner,  and  there  are  dyestuffs  which  exhibit 
the  characteristics  of  more  than  one;  for  instance,  there  are  dyes 
which  may  be  dyed  in  an  acid  bath,  and  would  consequently 
be  considered  as  acid  dyes,  but  which  also  dye  on  metallic  mor- 
dants, and  hence  would  also  be  included  among  the  mordant 
colors. 

Again,  basic  ctyres  may  also  be  dyed  in  baths  more  or  less 
strongly  acid;  and  substantive  dyes  may  be  dyed  (on  wool,  for 
instance)  from  neutral,  acid,  or  alkaline  baths,  or  may  even  be 
dyed  on  mordants.  So  it  may  be  seen  that  it  is  not  such  a 
simple  matter,  after  all,  to  quickly  decide  as  to  what  class  a 
dyestuff  is  to  be  referred.  This  problem  can  only  be  solved  by 
a  series  of  systematic  tests,  which  should  be  carried  out  in  the 
following  manner: 

A  solution  of  the  dyestuff  should  be  made  of  a  strength  of 
about  5  grams  per  litre,  using  distilled  water  as  the  solvent. 
The  solution  is  best  made  by  first  boiling  the  coloring-matter 
with  about  200  cc.  of  the  water  for  ten  to  fifteen  minutes,  and 
then  diluting  the  solution  to  one  litre  by  the  addition  of  cold 
water.  The  following  dye-tests  are  then  carried  out  with  this 
solution : 

(a)  A  test-skein  of  scoured  woolen  yarn  is  mordanted  by  boil- 
ing for  one-half  hour  in  a  bath  containing  3  per  cent,  of  chrome 
and  4  per  cent,  of  tartar;  washed  well,  and  then  dyed  in  a  bath 
containing  i  per  cent,  of  the  dyestuff.     If  a  skein  of  woolen  yarn 
becomes  dyed,  and  especially  if  most  of  the  color  is  extracted  from 
the  bath,  the  dyestuff  in  question  may  belong  to  the  mordant- 
dyeing  class,  though  the  certainty  of  this  can  only  be  ascertained 
by  the  succeeding  tests.     If,  however,  the  skein  in  this  test  does 
not  become  dyed,  which  is  hardly  likely,  then  it  is  positively 
known  that  the  coloring-matter  under  examination  is  not  a  mor- 
dant dye. 

(b)  A  second  test-skein  of  woolen  yarn  is  dyed  in  a  bath  con- 
taining 10  per  cent,  .of  glaubersalt  and  4  per  cent,  of  sulphuric 


THE   TESTING  OF  DYESTUFFS.  2/1 

acid,  together  with  i  per  cent,  of  the  dyestuff;  the  material  is 
boiled  for  one-half  hour,  then  squeezed  out  and  washed  well.  If 
the  wool  remains  undyed  in  this  case,  but  was  dyed  in  test  (a), 
almost  positive  assurance  is  afforded  that  the  coloring-matter  in 
question  is  a  mordant  dyestuff.  If,  however,  the  wool  is  dyed, 
the  coloring-matter  may  be  either  an  acid  dyestuff  belonging  to 
the  after-chromed  variety,  or  it  might  also  be  a  basic  or  a  sub- 
stantive dye.  This  must  be  determined  by  the  subsequent  tests. 
If  the  result  of  these  two  tests  leads  to  the  indication  of  a  mor- 
dant dyestuff,  this  may  be  confirmed  by  boiling  a  few  cubic 
centimeters  of  the  dye  solution  with  separate  solutions  of  chro- 
mium acetate  and  aluminium  sulphate;  if  the  dyestuff  belongs  to 
the  mordant  class,  there  will  be  a  precipitate  of  a  color-lake  in 
each  case.  If  there  is  no  precipitate,  this  would  indicate  that  any 
dyeing  obtained  on  the  mordanted  wool  in  test  (a)  does  not  pro- 
ceed from  the  presence  of  a  mordant  dye.  If  the  skeins  are  dyed 
in  both  tests  (a)  and  (b),  and  the  dyestuff  solution  also  causes  the 
precipitation  of  a  color-lake  with  the  salts  of  chromium  and 
aluminium,  then  it  may  reasonably  be  concluded  that  the  coloring- 
matter  in  question  is  a  mordant  dyestuff  which  also  dyes  wool 
from  an  acid  bath.  If  no  color-lake,  however,  is  formed  with 
the  metallic  salts,  then  the  dyestuff  is  probably  an  acid  color. 

(c)  A  test-skein  of  woolen  yarn  is  dyed  in  a  bath  containing 
i  per  cent,  of  the  dyestuff  and  10  per  cent,  of  glaubersalt,  being 
boiled  for  one-half  hour,  then  squeezed  and  washed  well.     If  the 
wool  remains  undyed  in  this  case,  it  indicates  a  mordant  dye,  as 
in  the  previous  test  (there  are,  however,  certain  substantive  dyes 
which  leave  wool  practically  undyed  under  such  conditions,  and 
consequently,  before  judging  definitely  that  the  dyestuff  belongs 
to  the  mordant  class,  the  fact  should  be  confirmed,  as  before 
described,  by  the  precipitation  of  the  metallic  color-lake) .     If  the 
skein  remains  undyed  in  this  test,  but  was  dyed  in  test  (b),  the 
dyestuff  is  probably  an  after-treated  mordant  dye.     If  the  skein 
is  dyed  in  test  (c) ,  it  may  be  either  an  acid,  substantive,  or  basic 
dye.     If  the  first,  it  would  also  have  been  dyed  in  test  (b). 

(d)  A  skein  of  cotton  yarn  is  dyed  in  a  bath  containing  i  per 


2/2  DYEING  AND    TEXTILE  CHEMISTRY. 

cent,  of  the  dyestuff  and  10  per  cent,  of  common-salt;  boil  for  one- 
half  hour,  then  squeeze,  and  wash  well  in  water,  and  then  in  a 
dilute  lukewarm  soap  bath.  If  the  cotton  is  not  dyed,  the  dye 
may  belong  to  either  the  mordant,  the  acid,  or  the  basic  class.  If 
to  the  first,  its  nature  would  have  already  been  indicated  by  the 
previous  test.  If  to  the  second,  it  would  also  have  dyed  the  wool 
in  test  (b),  and  probably  in  test  (c).  If  to  the  third,  the  wool  in 
test  (c),  and  probably  also  in  test  (6),  would  have  been  dyed.  If 
the  cotton  skein,  however,  in  this  test  is  well  dyed  and  retains  its 
color  after  soaping,  it  indicates  that  the  dyestuff  under  examina- 
tion belongs  to  the  substantive  class. 

(e)  A  skein  of  cotton  yarn  is  worked  in  a  bath  containing  4  per 
cent,  of  tannic  acid  for  one-half  hour  at  180°  F.,  then  squeezed 
and  worked  for  ten  minutes  in  a  cold  bath  containing  2  per  cent, 
of  tartar  emetic,  then  squeezed  and  well  washed.  This  mor- 
danted cotton  skein  is  then  dyed  in  a  bath  containing  i  per  cent, 
of  the  dyestuff  for  one-half  hour  at  160°  F.,  after  which  it  is 
squeezed  and  well  washed.  If  the  cotton  becomes  dyed  in  this 
test,  and  the  dye-bath  is  rapidly  and  rather  completely  exhausted, 
the  dyestuff  may  be  regarded  as  a  basic  dye,  in  which  case  the 
wool  in  test  (c)  would  also  be  dyed,  though  with  some  basic  dyes 
only  slightly  so,  and  the  cotton  in  test  (d)  would  remain  practically 
undyed.  If  the  cotton  skein  in  this  test  remains  undyed  or  is 
only  slightly  dyed,  the  dye  may  be  either  an  acid  or  a  mordant 
color,  the  distinction  between  which  would  have  already  been 
made  in  the  previous  tests. 

Experiment  142.  Chemical  Method  of  Distinguishing  between 
Acid  and  Basic  Dyestuffs.  —  These  two  classes  of  dyes  may  be 
rather  easily  distinguished  by  certain  chemical  tests  as  follows: 

(i)  Basic  dyes  are  not  removed  from  an  acidulated  aqueous 
solution  by  agitation  with  ether,  whereas  acid  dyes  are  taken  up 
by  the  latter.  Carry  out  the  test  as  follows :  Take  a  small  quantity 
of  Acid  Violet  (a  portion  the  size  of  a  grain  of  wheat  is  sufficient) , 
and  dissolve  in  about  5  cc.  of  dilute  sulphuric  acid;  then  add 
5  cc.  of  ether  and  shake  well.  After  settling,  notice  that  the 
layer  of  ether  has  taken  up  the  coloring-matter,  showing  the 


THE   TESTING  OF  DYESTUFFS.  2?$ 

presence  of  an  acid  dye.  Repeat  the  test,  using  Methylene  Blue, 
and  notice  that  the  ethereal  layer  is  not  colored.  A  sample 
containing  a  mixture  of  acid  and  basic  dye  (which,  however,  is 
hardly  likely,  as  dyes  of  different  classes  are  seldom  mixed 
together)  may  be  completely  separated  by  this  test,  the  acid  dye 
being  completely  extracted  by  the  ether. 

(2)  Caustic    soda   precipitates    most   basic   dyes   from   their 
aqueous  solutions  (the  safranine  class  excepted),   whereas  acid 
dyes  are  not  so  precipitated.     Take  about  5  cc.  of  an  aqueous 
solution  of  Acid  Violet  in  a  test-tube,  add  about  5  cc.  of  caustic 
soda  solution  (1:10)  and  warm  gently.     Notice  that  the  solution 
remains  clear.     Repeat  the  test,  using  a  solution  of  Magenta, 
and  notice  that  a  precipitate  is  formed.      Repeat  the  test  again, 
using  a  dilute  solution  of  Safranine,  and  notice  that  no  precipitate 
is  produced.     (In  the  latter  test,  if  a  concentrated  solution  of 
Safranine  is  used,  a  precipitate  will  form.) 

(3)  Aqueous    solutions    of    basic    dyes    are    precipitated    by 
addition  of  the  so-called  "  tannin  reagent,"   whereas  acid  dyes 
are  not  so  precipitated.     This  is  probably  the  best  means  of 
separating  basic  from  acid  dyes.   The  tannin  reagent  is  prepared 
by  dissolving  25  grams  of  tannic  acid  and  25  grams  of  sodium 
acetate  in  250  cc.  water.     Add  a  few  drops  of  this  reagent  to  a 
dilute   (i  per  cent.)  solution  of  Acid  Violet   and  warm  gently; 
notice  that  no  precipitate  is  formed.     Repeat  the  test,  using  a 
dilute  solution  of  Magenta;  the  latter  will  produce  a  precipitate. 

Test  several  samples  of  unknown  dyes  in  order  to  determine 
whether  they  belong  to  the  acid  or  the  basic  class. 

Experiment  143.  Detection  of  Adulterations  in  Dyestuffs.  — 
Commercial  dyestuffs  are  frequently  adulterated  with  common- 
salt  (sodium  chloride),  glaubersalt  (sodium  sulphate),  soda  ash 
(sodium  carbonate),  dextrin,  starch,  sugar,  and  Epsom  salts. 
The  presence  of  such  substances,  however,  does  not  always 
indicate  intentional  adulteration;  for  in  their  manufacture  many 
dyes  are  " salted  out"  from  solution,  or  precipitated  by  strong 
brine  solutions,  and  therefore  would  nearly  always  show  the 
presence  of  varying  amounts  of  common-salt.  Again,  in  the 


2/4  DYEING  AND    TEXTILE  CHEMISTRY. 

manufacture  of  dyestuffs,  it  is  desirable  to  prepare  products 
of  uniform  strength,  and  as  the  different  lots  of  manufactured 
dye  seldom  show  exactly  the  same  strength,  a  definite  standard 
must  be  adopted  to  which  weaker  lots  are  brought  up  by  the 
addition  of  a  stronger  dye  while  too  strong  a  lot  of  dyestuff  is 
diluted  to  the  standard  by  the  addition  of  suitable  neutral  salts. 
The  occurrence  of  a  large  proportion  of  the  above-mentioned 
salts  in  the  dyestuff  must,  however,  be  taken  as  indicating 
intentional  adulteration.  For  basic  dyes  sodium  chloride  and 
dextrin  are  chiefly  used;  for  the  acid  dyes  sodium  sulphate  is 
employed,  and  for  the  substantive  dyes  either  sodium  chloride 
or  sulphate  may  be  used.  Dextrin  in  some  cases  is  added 
to  increase  the  solubility  of  the  dyestuff. 

(A)  Detection  oj  Sodium  Chloride.  —  As  silver  nitrate  forms 
an  insoluble  white  precipitate  of  silver  chloride  when  added 
to  a  solution  of  common-salt,  this  reagent  is  used  for  the  test. 
In  many  cases  the  test  may  be  carried  out  by  simply  dissolving 
a  small  quantity  of  the  dyestuff  in  water,  adding  a  few  drops 
of  nitric  acid  (to  prevent  the  precipitation  of  any  other  salt  of 
silver  besides  the  chloride),  and  then  a  few  drops  of  a  solution 
of  silver  nitrate,  when  the  production  of  a  white  precipitate  will 
indicate  the  presence  of  a  chloride.  This  method,  however, 
is  not  always  reliable,  as  many  dyestuffs  are  hydrochlorides 
of  color-bases  (basic  dyes),  or  give  insoluble  salts  of  silver,  in 
which  cases  the  formation  of  a  white  precipitate  would  not 
necessarily  indicate  the  presence  of  common-salt.  It  is  best  to 
ignite  a  portion  of  the  dyestuff  in  a  porcelain  crucible,  so  as  to 
burn  off  all  volatile  and  organic  matter,  leaving  only  mineral 
matter  in  the  ash.  Dissolve  the  ash  in  water,  add  a  few  drops 
of  nitric  acid  and  then  the  silver  nitrate;  a  white  precipitate 
of  silver  chloride  will  be  formed  if  common-salt  is  present.  A 
few  dyes,  such  as  the  eosins,  leave  chlorides  (or  bromides  or 
iodides)  in  the  ash  after  ignition;  hence  this  test  would  not  be 
satisfactory.  For  such  dyes,  the  aqueous  solution  of  the  coloring- 
matter  should  be  acidulated  with  dilute  sulphuric  acid,  then 
shaken  up  with  ether.  The  dyestuff  will  be  dissolved  out  by  the 


THE   TESTING  OF  DYESTUFFS.  2/5 

ether,  leaving  any  common-salt  which  may  be  present  in  the 
aqueous  layer.  The  latter  may  be  removed  and  tested  with 
silver  nitrate  as  described  above.  If  the  dyestuff  is  soluble  in 
alcohol,  the  coloring-matter  may  first  be  extracted  by  warming 
with  this  solvent,  and  the  test  for  common-salt  may  then  be 
made  with  the  residue. 

(1)  Testing  for   Salt   in   Acid    Yellow.  —  Dissolve   a    small 
portion  of  the  pure  dyestuff  in  water,  add  a  couple  of  drops 
of  dilute  nitric  acid  and  a  few  drops  of  silver  nitric  solution;  no 
precipitate  will  be  produced.     Repeat  the  test,  using  a  sample 
of  the  dyestuff  containing  common-salt,  and  notice  the  formation 
of  a  white  precipitate  of  silver  chloride  (which  will  be  more  or 
less  colored  by  the  dyestuff). 

(2)  Testing  for  Salt  in  Magenta.  —  Dissolve  a  small  quantity 
of    the    pure    dye    in    water,   and    test  with    silver  nitrate    as 
above.     As  the  dye  itself  is  the  hydrochloride  of  the  color-base, 
a  precipitate  of  silver  chloride  will  be  formed,  though  no  common- 
salt  is  present.     Place  a  small  quantity  of  the  dyestuff  in  a  porce- 
lain crucible,  and  ignite  until  all  organic  matter  is  completely 
burned  away;  dissolve  the  ash  in  a  small  quantity  of   water 
acidulated  with  a  few  drops  of  nitric  acid,  and  test  with  silver 
nitrate;  no  precipitate  will  be  produced.     Repeat  this  test,  using 
a  sample  of    Magenta  containing  common-salt   and  note   the 
formation  of  a  precipitate  of  silver  chloride. 

(3)  Testing  for   Salt    in   Eosin.  —  Place    a    small    quantity 
of   pure   Eosin   in    a   porcelain  crucible    and    ignite   as  above 
described;    on    dissolving    the    ash    in    water  and   testing  with 
silver  nitrate  in  the  usual  manner,  a  precipitate  will  be  formed 
though  no  common-salt  is  present.     Next  take  a  small  quantity 
of  the  Eosin,  dissolve  in  10  cc.  of  water  in  a  test-tube  (or  better, 
a  stoppered  separatory  funnel),  add  5  cc.  of  ether  (be  sure  the 
solution  is  cold  before  adding  the  ether),  shake  well  and  allow 
to  stand.     The  ethereal  layer,  containing  the  dyestuff  in  solution 
will  collect  on  top,  while  the  aqueous  layer  will  remain  at  the 
bottom.     If  the  color  is  not  well  extracted   from  the  bottom 
layer  pour  off  the  ethereal  layer  and  repeat  the  extraction  with 


2/6  DYEING  AND    TEXTILE  CHEMISTRY. 

fresh  ether.  Withdraw  the  aqueous  layer  by  means  of  a  pipette, 
and  test  it  with  silver  nitrate  as  usual;  no  precipitate  will  be 
produced.  Repeat  this  test,  using  a  sample  of  Eosin  containing 
common-salt,  and  notice  that  a  precipitate  of  silver  chloride  will 
be  formed. 

(4)  Testing  for  Salt  in  Orange  II.  —  Place  a  small  sample  of 
the  pure  dye  in  a  test-tube  and  dissolve  in  10  cc.  of  warm  alco- 
hol; it  should  be  completely  soluble.  Repeat  this  test,  using  a 
sample  of  the  dye  containing  common-salt;  notice  that  a  residue 
is  left.  Dissolve  this  in  water  and  test  with  silver  nitrate  as 
usual;  a  precipitate  of  silver  chloride  will  be  produced. 

(B)  Detection  of  Sodium  Sulphate.  —  Sulphates  in  general 
are  detected  by  the  addition  of  barium  chloride  to  their  solution, 
whereby  an  insoluble  white  precipitate  of  barium  sulphate  is 
formed.  The  presence  of  sulphates  in  the  ash  of  a  dyestuff 
does  not  necessarily  indicate  adulteration  with  glaubersalt,  as 
many  dyes  are  themselves  sulphonated  compounds,  and  on  igni- 
tion leave  sodium  sulphate  in  the  ash.  The  best  procedure 
for  testing  for  glaubersalt  in  a  dyestuff  is  as  follows:  Dissolve 
some  pure  Benzopurpurin  in  a  small  amount  of  water,  add  a  few 
drops  of  dilute  hydrochloric  acid  (to  prevent  other  compounds 
of  barium  being  precipitated),  then  a  solution  of  barium  chloride 
as  long  as  a  precipitate  forms.  This  precipitate,  which  consists 
of  barium  sulphonate,  is  filtered  off,  washed,  and  boiled  with 
a  solution  of  ammonium  carbonate.  This  converts  it  into 
barium  carbonate;  filter  again,  and  wash  the  residue  of  barium 
carbonate,  and  then  add  dilute  hydrochloric  acid  to  the  latter, 
when  it  should  be  completely  dissolved.  Repeat  the  test,  using 
a  sample  of  Benzopurpurin  containing  glaubersalt.  The  precip- 
itate obtained  with  barium  chloride,  in  this  case,  consists  of  a 
mixture  of  barium  sulphonate  and  barium  sulphate.  On  boiling 
this  with  ammonium  carbonate,  only  the  sulphonate  is  converted 
into  barium  carbonate,  and  on  finally  dissolving  in  hydrochloric 
acid,  the  barium  sulphate  will  be  left  as  an  insoluble  residue, 
thus  showing  the  presence  of  glaubersalt  in  the  original  dye. 
Another  method  for  testing  for  sulphates  is  to  precipitate  the 


THE   TESTING  OF  DYESTUFFS. 

dyestuff  from  its  aqueous  solution  by  the  addition  of  pure  com- 
mon-salt to  complete  saturation.  The  precipitated  dyestuff  with 
excess  of  salt  is  filtered  off,  the  filtrate  acidulated  with  a  few 
drops  of  hydrochloric  acid  and  tested  with  barium  chloride 
solution.  This  formation  of  a  white  precipitate  will  indicate 
the  presence  of  glaubersalt  in  the  original  dyestuff.  This 
method,  however,  is  not  very  satisfactory,  as  it  is  usually  difficult 
to  precipitate  the  dyestuff  completely  from  its  solution.  Another 
method  of  testing  for  sulphates  is  to  dissolve  the  dyestuff  in 
strong  warm  alcohol  (where  this  is  possible),  and  as  glaubersalt 
is  insoluble  in  alcohol  it  will  be  left  as  a  white  residue  (as  in  the 
case  of  common-salt).  This  is  to  be  dissolved  in  water  and 
tested  with  barium  chloride  in  the  usual  manner. 

(C)  Detection  of  Soda  Ash.  —  This  substance  is  frequently 
added   to    eosins,   and  sometimes   to    substantive   dyes.     It    is 
detected  by  dissolving  a  sample  of  the  dye  in  water,  and  adding 
hydrochloric  acid  to  the  solution,  when  an  effervescence  will  be 
produced  due  to  the  liberation  of  carbon  dioxide  gas  from  the 
carbonate  present.     For  example:    Dissolve  some  pure  Eosin  in 
a  little  water  and  add  a  few  drops  of  dilute  hydrochloric  acid; 
no  effervescence  will  occur.     Repeat  the  test,  using  a  sample 
of  Eosin  containing  sodium  carbonate;  a  vigorous  effervescence 
will  be  noted. 

(D)  Detection  of  Epsom  Salts.  —  This  consists  of  magnesium 
sulphate,  and  is  occasionally  added  as  an  adulterant  to  dyes. 
The  presence  of  the  sulphate  is  detected  in  the  manner  described 
under  the  test  for  sodium  sulphate.     The  presence  of  the  magne- 
sium is  shown  in  the  following  manner:   Place   a  portion  of 
Methyl  Violet  containing  magnesium  sulphate  in  a  porcelain  cru- 
cible; ignite  until  all  carbon  and  volatile  matter  is  burned  away. 
Dissolve  the  ash  in  hot  dilute  hydrochloric  acid,  and  filter,  if 
necessary.     Neutralize  the  filtrate  with  ammonia  water  and  add 
a  solution  of  sodium  phosphate.     After  standing  for  a  short  time 
a  crystalline  precipitate  (of  magnesium  ammonium  phosphate) 
is  formed,  showing  the  presence  of  a  magnesium  salt  in  the 
original  dyestuff. 


DYEING   AND    TEXTILE   CHEMISTRY. 

(E)  Detection    of  Dextrin.  —  This  impurity  can    usually  be 
recognized  by  the  peculiar  odor  dextrin  gives  on  dissolving  the 
dye  in  warm  water.     It  may  best  be  tested  for  as  follows :  Take  a 
small  sample  of  Methyl  Violet  containing  dextrin;  extract  the 
coloring-matter  with  absolute  alcohol;  the  dextrin  will  be  left  as 
a  residue.     Dissolve  the  latter  in  a  small  quantity  of  warm  water, 
and  notice  the  peculiar  odor  of  the  dissolving  dextrin.     Dextrin 
is  frequently  added  to  paste  dyes  and  to  basic  dyes. 

(F)  Detection  of  Starch.  —  This  impurity  may  be  separated 
from  the  dyestuff  by  treating  with  cold  water,  in  which  the  starch 
is  insoluble.     It  may  then  be  recognized  as  follows:  Take  a 
sample  of  Eosin  containing  starch;  extract  the  coloring-matter 
with  cold  water;  dissolve  the  residue  of  starch  in  a  little  boiling 
water,  and  add  a  few  drops  of  a  solution  of  iodine  in  potassium 
iodide.      A  deep  blue  color   will  be  produced,   indicating  the 
presence  of  starch. 

(G)  Detection  of  Sugar.  —  This  impurity  is  frequently  added 
to  crystalline  dyes,  as  it  occurs  in  the  crystalline  form  itself.     Its 
presence  may  be  shown  as  follows:  Take  a  sample  of  Magenta 
containing  sugar;  extract  with  absolute  alcohol.     The  dyestuff 
passes  into  solution,  whereas  the  sugar  remains  practically  insol- 
uble, and  becomes  nearly  colorless.     Heat  the  residue  in  a  test- 
tube  and  notice  the  odor  of  caramel,  indicating  the  presence  of 
sugar. 

Experiment  144.  Determination  of  the  Capillary  Speed  of 
Dyestuffs.  —  By  the  capillary  speed  of  a  dyestuff  is  meant  the 
height  to  which  its  solution  will  rise  in  a  given  time  through 
porous  paper  (filter  or  blotting  paper).  This  factor  is  only  a 
relative  number,  and  is  usually  compared  with  pure  water  as  a 
standard. 

Take  five  strips  of  blotting  paper  measuring  5  inches  in  length 
and  one-half  inch  in  width;  make  a  mark  on  each  strip  i  inch 
from  the  end.  Immerse  one  of  these  strips  in  a  small  beaker 
containing  pure  water  so  that  the  surface  of  the  water  comes 
exactly  to  the  i-inch  mark  on  the  paper.  Sustain  the  strip  in  a 
perpendicular  position,  and  allow  it  to  remain  in  the  water  for 


THE    TESTING   OF   DYESTUFFS. 


2/9 


just  one  minute.  Then  measure  the  height  to  which  the  water 
has  risen  on  the  paper.  Repeat  the  test  with  a  fresh  strip  of  paper, 
using  a  one  per  cent,  solution  of  magenta,  and  after  one  minute 
measure  the  height  to  which  the  color  has  ascended.  Repeat  the 
test  further  on  one  per  cent,  solutions  of  Naphthol  Yellow,  Acid 
Violet,  and  Malachite  Green.  Tabulate  the  results  obtained  as 
follows : 


Solution. 

Distance  color  rises. 

Compared  with  water 
as=  100. 

Water 

Magenta 

Naphthol  Yellow  S 

Acid  Violet  

Malachite  Green  .... 

QUIZ  23. 

687.  Describe  the  method  of  determining  the  comparative  money  value  of 
a  dyestuff. 

688.  Suppose  dyestuff  "A"  required  16  cc.,  "B"  10  cc.,  and  "C"  12  cc.  of 
their  respective  solutions  to  give  the  same  depth  of  shade  on  testing;  what 
would  be  the  values  of  "B"  and  "C"  if  "A"  is  quoted  at  36  cents  per  pound? 

689.  If  several  successive  additions  to  the  dye-bath  have  been  made  to 
secure  a  match,  why  is  it  best  to  repeat  the  dyeing  using  the  required  amount  of 
dyestuff  in  a  single  addition  ? 

690.  What  is  meant  by  the  "exhaust  test"  in  valuing  dyes,  and  what  is  its 
purpose  ? 

691.  What  is  the  purpose  of  mixing  different  dyes  together  before  sale? 
Does  evidence  of  admixture  always  indicate  adulteration  ? 

692.  Describe  the  tests  given  for  the  detection  of  mixed  dyes. 

693.  What  tests  would  you  make  to  identify  a  basic  dye;  an  acid  dye;  a 
substantive  dye;  a  mordant? 

694.  What  are  the  principal  substances  used  for  the  adulteration  of  dye- 
stuffs?    Does  the  presence  of  common-salt  in  a  dyestuff   always   indicate 
intentional  adulteration  ?    Why  ? 

695.  What  is  the  general  test  for  the  detection  of  sodium  chloride  ?     Is  this 
applicable  to -all  dyestuff s? 

696.  How  would  you  test  for  the  presence  of  common-salt  in  Acid  Yellow 
and  similar  dyestuffs  ? 


280  DYEING  AND    TEXTILE   CHEMISTRY. 

697.  How  would  you  test  for  the  presence  of  common-salt  in  Magenta  and 
such  dyes  that  consist  of  hydrochlorides  ? 

698.  Give  the  method  for  the  testing  of  common-salt  in  the  eosin  group  of 
dyes. 

699.  In  case  a  dyestuff  is  soluble  in  alcohol,  how  may  the  presence  of  com- 
mon-salt be  shown? 

700.  What  is  the  general  method  for  the  detection  of  sulphates?    What 
other  sulphate  besides  glaubersalt  may  be  present  in  dyes? 

701.  Why  should  not  the  direct  test  for  sulphates  be  made  with  dyestuffs? 
What  is  meant  by  a  sulphonate  ? 

702.  Describe  the  method  of  testing  for  glaubersalt  in  a  dyestuff. 

703.  How  may  glaubersalt  be  detected  in  a  dyestuff  by  the  "salting-out" 
process  ?    In  case  the  dyestuff  is  soluble  in  alcohol  what  process  may  be  used  ? 

704.  How  may  the  presence  of  soda  ash  be  detected  in  a  dyestuff?    What 
classes  of  dyes  are  subject  to  this  adulteration  ? 

705.  What  is  Epsom  salts  ?     How  may  its  presence  be  shown  in  a  dyestuff  ? 

706.  Dextrin  is  used  as  an  adulterant  with  what  classes  of  dyes?    How 
may  its  presence  be  detected  ? 

707.  How  is  the  presence  of  starch  in  a  dyestuff  detected? 

708.  What  classes  of  dyes  are  adulterated  with  sugar?    How  is  this  sub- 
stance detected  ? 


SECTION  XXIV. 
CHEMICAL  REACTIONS  OF  DYESTUFFS. 

IN  order  to  identify  any  particular  dyestuff  it  is  necessary  to 
test  it  with  various  chemical  reagents,  whereby  a  series  of  chemical 
reactions  are  obtained,  usually  based  on  color  changes.  Tabu- 
lated reactions  have  been  prepared  of  the  various  dyestuffs,  and 
by  reference  to  these  it  is  usually  possible  to  identify  any  individual 
coloring  matter.  Difficulty,  however,  will  be  experienced  with  col- 
oring matters  containing  mixtures  of  two  or  more  dyestuffs,  as  the 
reaction  of  one  of  the  dyes  in  the  mixture  may  obscure  the  reac- 
tion of  the  other  dye.  In  the  case  of  many  mixtures  it  is  practically 
impossible  to  determine  accurately  the  exact  dyestuffs  present 
unless  some  method  is  available  for  the  separation  of  the  dyes. 

Considerable  evidence  as  to  the  identity  of  a  dyestuff  is  fur- 
nished by  its  dyeing  properties  toward  cotton  and  wool.  In  this 
manner  it  will  be  possible  to  determine  if  the  dyestuff  in  question 
is  acid  or  basic,  etc.,  and  this  method  of  classification  will  elimi- 
nate many  uncertain  possibilities. 

In  the  following  experiments,  to  illustrate  the  results  of  the 
reactions  given,  the  dyestuff  Auramine  is  taken  as  an  example. 

Experiment  145.  Solubility  Tests.  —  (a)  With  Water.  —  Take 
about  o.i  gram  of  the  dyestuff  and  add  to  20  cc.  of  distilled  water 
in  a  test-tube;  shake  well,  and  then  boil;  observe  the  relative 
solubility.  Auramine  is  very  soluble,  (b)  With  Alcohol.  — 
Repeat  the  test,  using  alcohol  in  place  of  water;  note  the  relative 
solubility  and  the  color  of  the  solution.  Auramine  is  very  soluble 
with  a  yellow  color,  (c)  With  Ether.  —  Repeat  the  test,  using 
ether;  Auramine  is  insoluble,  (d)  With  Benzene.  —  Repeat  the 
test,  using  benzene;  Auramine  is  insoluble. 

Experiment  146.  Reaction  with  Sulphuric  Acid.  —  (a)  With 
Concentrated  Acid.  —  A  small  quantity  (on  the  tip  of  a  penknife 

281 


282  DYEING  AND    TEXTILE  CHEMISTRY. 

blade)  of  the  dyestuff  is  added  to  about  5  cc.  of  pure  concentrated 
sulphuric  acid  in  a  test-tube;  shake  well  and  note  the  color  of 
the  solution  obtained.  Auramine  dissolves  with  effervescence 
(due  to  evolution  of  hydrochloric  acid  gas),  and  gives  a  colorless 
solution,  (b)  On  Dilution  with  Water.  —  Add  a  drop  or  two  of  the 
strong  acid  solution  as  obtained  above  to  about  10  cc.  of  water  in 
a  test-tube,  and  note  the  reaction  which  occurs.  Auramine  on 
dilution  gives  a  yellow  color,  (c)  On  Heating.  —  The  remainder 
of  the  strong  acid  solution  is  gradually  heated  to  the  boiling 
point.  Auramine  furnishes  a  pale  brownish  yellow  solution. 

Experiment  147.  Reaction  with  Hydrochloric  Acid.  —  Use  an 
aqueous  solution  of  the  dyestuff  containing  i  gram  of  dye  per  litre. 
To  5  cc.  of  this  solution  add  5  cc.  of  a  solution  of  hydrochloric 
acid  (containing  100  cc.  of  the  strong  acid  per  litre) ;  allow  to 
stand  for  10  minutes,  and  note  what  reaction,  if  any,  occurs. 
Auramine  remains  unchanged.  Now  heat  the  solution  to  boiling 
and  note  any  change  that  occurs;  Auramine  becomes  decolorized. 

Experiment  148.  Reaction  with  Nitric  Acid.  —  To  5  cc.  of  the 
aqueous  solution  of  the  dyestuff  add  5  cc.  of  a  solution  of  nitric 
acid  (containing  50  cc.  of  the  strong  acid  per  litre),  and  carry 
out  the  test  as  above.  Auramine  remains  unchanged  cold;  on 
boiling  it  gives  a  pale  yellow  solution. 

Experiment  149.  Reaction  with  Sodium  Hydrate.  —  Carry  out 
the  test  as  above  described,  using  5  cc.  of  a  solution  of  sodium 
hydrate  (containing  100  cc.  of  sodium  hydrate  of  sp.  gr.  1.3  to 
one  litre).  If  a  precipitate  is  formed,  add  about  2  cc.  of  ether, 
and  shake;  observe  if  the  ether  extracts  the  precipitated  color 
from  the  caustic  soda;  then  add  a  drop  or  two  of  acetic  acid  to 
the  ethereal  layer,  and  note  any  change.  Auramine  gives  a 
white  precipitate,  extracted  with  ether,  becoming  yellowish  on 
addition  of  acetic  acid. 

Experiment  150.  Reaction  with  Ammonia.  —  Repeat  the  test 
as  above  given,  using  5  cc.  of  commercial  ammonia  water.  Aura- 
mine  undergoes  the  same  reactions  as  with  sodium  hydrate. 

Experiment  151.  Reaction  with  Sodium  Carbonate.  —  Repeat 
the  test  as  given  above,  using  5  cc.  of  a  solution  of  sodium  car- 


CHEMICAL  REACTIONS  OF  DYESTUFFS.  283 

bonate  (100  grams  per  litre).  If  a  precipitate  is  formed  with  the 
cold  solution,  heat  to  boiling  and  observe  if  this  causes  the  pre- 
cipitate to  redissolve.  Auramine  gives  a  milky  yellow  precipitate 
which  remains  insoluble  on  heating. 

Experiment  152.  Reaction  with  Tannin  Reagent.  —  Carry  out 
the  test,  using  5  cc.  of  a  solution  containing  100  grams  of  tannic 
acid  dissolved  in  500  cc.  of  water  and  mixed  with  a  solution  of 
100  grams  of  sodium  acetate  in  500  cc.  of  water.  I'f  a  precipitate 
is  formed  heat  to  boiling  and  note  any  change  in  its  character. 
Auramine  gives  a  yellow  precipitate,  which  on  boiling  becomes 
brown,  resinous,  and  partially  soluble.  This  reagent  is  useful  for 
distinguishing  between  acid  and  basic  dyes,  as  the  latter  alone 
give  a  precipitate. 

Experiment  153.  Reaction  with  Alum.  —  Add  to  the  aqueous 
solution  of  the  dyestuff  5  cc.  of  a  solution  of  alum  (containing  50 
grams  per  litre).  If  a  precipitate  is  formed,  heat  to  boiling,  and 
note  any  change  that  may  occur.  Auramine  remains  unchanged 
with  the  alum  solution.  Many  of  the  acid  dyes  and  nearly  all 
of  the  mordant  dyes  give  characteristic  precipitates  with  alum. 

Experiment  154.  Reaction  with  Potassium  Bichromate.  — 
Add  to  the  aqueous  solution  of  the  dyestuff  5  cc.  of  a  solution 
containing  50  grams  of  potassium  bichromate  per  litre.  If  a 
precipitate  is  formed,  heat  to  boiling,  and  note  any  change  that 
may  occur.  Auramine  give  a  yellow  precipitate,  which  on 
heating  becomes  resinous  and  for  the  most  part  dissolves.  The 
majority  of  the  basic  dyes  are  precipitated  by  this  reagent,  as  is 
also  the  case  with  most  of  the  mordant  dyes;  only  a  few  of  the 
acid  dyes  are  thus  precipitated. 

Experiment  155.  Reaction  with  Ferric  Chloride.  —  Add  to  the 
aqueous  solution  of  the  dyestuff  5  cc.  of  a  solution  containing 
100  grams  of  ferric  chloride  per  litre;  note  the  reaction  and  then 
heat  to  boiling  and  observe  any  further  change.  Auramine 
remains  unchanged  in  the  cold  solution;  on  heating  the  solution 
becomes  turbid  and  of  a  brownish  yellow  color. 

Experiment  156.  Reaction  with  Stannous  Chloride.  —  Add  to 
the  aqueous  solution  of  the  dyestuff  5  cc.  of  a  solution  containing 


284  DYEING   AND    TEXTILE   CHEMISTRY. 

ioo  grams  of  stannous  chloride  per  litre  (with  •  sufficient  hydro- 
chloric acid  to  yield  a  clear  solution).  After  standing  10  minutes, 
heat  to  boiling,  and  note  the  reactions  which  occur.  Auramine 
remains  unchanged.  A  large  number  of  dyestuffs  either  give 
characteristic  precipitates,  or  become  decolorized. 

Experiment  157.  Reaction  with  Bleaching  Powder.  —  Add  to 
the  aqueous  solution  of  the  dyestuff  5  cc.  of  a  solution  of  bleaching 
powder  of  1.5°  Tw.  strength.  After  standing  for  10  minutes, 
heat  to  boiling,  and  note  any  changes  which  occur.  Auramine 
gives  a  dirty,  pale  yellow  precipitate,  which  on  heating  turns  to  a 
dirty  red  color. 

Experiment  158.  Reaction  with  Zinc  Dust.  —  Add  to  the 
aqueous  solution  of  the  dyestuff  about  i  gram  of  zinc  dust  and 
5  cc.  of  ammonia  water;  shake  well  and  then  heat  to  boiling; 
filter  at  once,  and  note  if  the  nitrate  if  decolorized  becomes  colored 
again  on  exposure  to  the  air.  Auramine  gives  a  colorless  nitrate, 
and  the  color  does  not  reappear  on  exposure  to  the  air;  but  the 
precipitate  left  on  the  filter  gradually  becomes  yellowish  on 
standing.  The  solutions  of  nearly  all  dyes  are  decolorized  by 
this  reagent,  and  many  dyes  give  a  characteristic  reappearance 
of  color  on  exposure  to  the  air.  The  loss  of  color  is  caused  by 
the  reduction  of  the  coloring-matter,  which  may  be  converted 
either  into  a  leuco  (colorless)  derivative  (which  allows  of  the 
original  dyestuff  being  again  formed  on  oxidation  in  the  air),  or 
be  entirely  destroyed.  In  the  latter  case  no  reappearance  of 
color  will  be  shown  on  oxidation. 

Experiment  159.  Reaction  with  Zinc  Dust  and  Acetic  Acid.  — 
Repeat  the  above  test  as  given,  using,  however,  5  cc.  of  acetic 
acid  in  place  of  the  ammonia.  Auramine  becomes  blue  on 
acid  reduction.  Many  dyestuffs  give  characteristic  colors  with 
this  test,  while  some  are  decolorized  completely.  In  many 
cases  the  original  colors  reappear  on  exposure. 

Test  the  following  dyestuffs  in  the  same  manner  as  outlined 
for  Auramine: 

Magenta  Benzopurpurin         Naphthol  Yellow  S 

Acid  Violet  4R        Alkali  Blue  Alizarin  Brown  SO 


CHEMICAL  REACTIONS  OF  DYESTUFFS.  285 

TABULATION    OF    RESULTS    WITH    CHEMICAL    REAGENTS. 


Tes1 

i. 

Auramine. 

2. 

Acid  Violet  4R. 

3- 
Alkali  Blue  R. 

I  Water. 

Very  sol. 

Quite  sol. 

Quite  sol. 

Solubility  in 
7 

Alcohol. 

Very  sol. 

Quite  sol. 

Quite  sol. 

Ether. 

Insoluble. 

Insoluble. 

Slightly  soluble. 

Benzene. 

Insoluble. 

Insoluble. 

Insoluble. 

Concentrated 
sulphuric 
acid. 

Solution. 
Dilution. 
Heating. 

Colorless. 
Yellow. 
Brown-yellow. 

Dark  brown. 
Violet. 
Dark     yellow- 
brown. 

Red  brown. 
Blue  ppt. 
Dark  brown  . 

Dilute  hydro- 

Cold. 

No  change. 

No  change. 

Blue  ppt. 

-    chloric  acid. 

Heating. 

Decolorized. 

No  change. 

Blue  ppt. 

Dilute     nitric    j 

Cold. 

No  change. 

No  change. 

Blue  ppt. 

acid.                i 

Heating. 

Pale  yellow. 

No  change. 

Turns  green. 

Sodium      hy- 

Cold. 
Extraction 

White  ppt. 
Color  extracted. 

Colorless. 

No  change. 

drate. 

with  ether. 

Ammonia. 

kCold. 

As  above. 

Colorless. 

0      J' 

Cold. 

Yellow     milky 

Sodium    car- 

bonate. 

Heating. 

ppt. 
No  change. 

Tannin       re- 

Cold. 

Yellow  ppt. 

No  change. 

No  change. 

agent. 

Heating. 

Brown,    resin- 

No change. 

ous;     partly 

sol. 

Alum. 

[Cold. 
.Heating. 

No  change. 
No  change. 

Darker. 
Same. 

Blue  ppt. 
Blue  ppt. 

Potassium  bi- 

fCold. 

Yellow  ppt. 

No  change. 

No  change. 

chromate. 

(Heating. 

Resinous; 

No  change. 

"•"&• 

mostly     dis- 

solves. 

Ferric    chlo- 

(Cold. 

No  change. 

ride. 

.Heating. 

Brown-yellow. 

Stannous 

fCold. 

No  change. 

No  change. 

chloride. 

•Heating. 

No  change. 

No  change. 

Blue  ppt. 

[Cold. 

Dirty    yellow 

Calcium     hy- 

pochlorite. 

Heating 

ppt. 
Dirty  red  color. 

Zinc  dust  and 
ammonia. 

[***'«*fc**»^« 

[Cold. 
Exposed. 
[Precipitate. 

Colorless. 
Colorless. 
Yellowish. 

Colorless. 
Same. 

Colorless. 
Blue. 

Zinc  dust  and 
acetic  acid. 

Cold. 
Exposed. 
Precipitate. 

Blue. 
No  change. 

Bluish  pink. 
Same. 

Colorless. 
Blue. 

SECTION  XXV. 

MISCELLANEOUS  TESTS  IN  DYEING. 

Experiment  160.  The  Amount  of  Dyestuff  Necessary  for  a 
Full  Shade.  —  This  factor  may  be  determined  by  dyeing  test- 
skeins  with  increasing  amounts  of  dyestuff  until  no  further 
increase  in  shade  is  observed.  Proceed  as  follows:  Use  six 
test-skeins  of  woolen  yarn  (No.  i  to  No.  6)  of  the  same  weight, 
dye  them  respectively  with  the  following  amounts  of  Acid  Violet, 
employing  the  usual  acid  bath  and  method  of  dyeing: 

No.  i,  with  i  per  cent,  of  dyestuff  (436). 
No.  2,  with  2  per  cent,  of  dyestuff  (437). 
No.  3,  with  3  per  cent,  of  dyestuff  (438). 
No.  4,  with  4  per  cent,  of  dyestuff  (439). 
No.  5,  with  5  per  cent,  of  dyestuff  (440). 
No.  6,  with  6  per  cent,  of  dyestuff  (441). 

After  dyeing  the  samples  are  compared,  and  note  is  taken  at 
which  point  the  shade  ceases  to  show  a  perceptible  increase. 
The  same  method  may  be  employed  in  other  classes  of  dyes, 
using  their  respective  methods  of  dyeing. 

Experiment  161.  To  Determine  the  Degree  of  Exhaustion 
of  the  Dye-bath.  —  By  the  exhaustion  of  the  dye-bath  is  meant 
the  relative  quantity  of  color  absorbed  by  the  fibre  during 
the  dyeing  process.  Proceed  as  follows:  Dye  a  test-skein  (442) 
of  woolen  yarn  with  3  per  cent,  of  Acid  Violet,  4  per  cent,  of  sul- 
phuric acid,  20  per  cent,  of  glaubersalt,  making  the  dye-bath  up 
to  exactly  300  cc.  and  taking  out  25  cc.  of  the  solution  before 
dyeing  to  preserve  for  comparison  in  a  test-tube.  Carry  out  the 
dyeing  operation  in  the  usual  manner;  squeeze  the  excess  of 
liquor  from  the  skein  back  into  the  dye-bath  so  as  not  to  lose  any 

286 


MISCELLANEOUS   TESTS  IN  DYEING.  287 

of  the  solution.  Make  up  the  bath  again  to  exactly  275  cc.; 
fill  a  graduated  calorimetric  tube  with  this  solution;  take  i  cc. 
of  the  original  dye-bath  in  another  similar  calorimetric  tube, 
and  dilute  the  latter  with  water  until  it  exhibits  the  same  inten- 
sity of  color  as  the  first  tube.  The  degree  of  dilution  required 
measures  the  degree  of  exhaustion  of  the  dye-bath.  For  example : 
i  cc.  of  the  original  solution  required  to  be  diluted  to  8.5  cc. 
to  show  the  same  intensity  of  color  as  the  exhausted  bath;  hence 
the  relative  amount  of  dye  left  in  the  bath  is  i  -r-  8.5  =  0.12, 
and  the  amount  absorbed  must  have  been  0.88  or  88  per  cent. 
Therefore  the  degree  of  exhaustion  in  this  case  would  be  88  per 
cent. 

Pour  the  liquor  taken  from  the  exhausted  bath  back  into  the  dye- 
bath,  and  without  further  addition  of  dyestuff  or  chemicals,  dye 
another  test-skein  of  woolen  yarn.  After  dyeing  a  portion  (443) 
compare  it  with  the  first  skein.  The  difference  in  intensity  of 
the  two  dyeings  will  represent  in  a  rough  manner  the  degree  of 
exhaustion.  Now  continue  the  dyeing  of  the  second  skein  (444) 
by  adding  to  the  bath  sufficient  dyestuff  to  bring  the  shade  up 
to  that  of  the  first  skein.  Besides  the  dyestuff  also  add  2  per  cent, 
more  of  sulphuric  acid,  as  some  of  the  acid  originally  added  will 
have  been  removed  by  the  first  dyeing.  Note  the  amount  of 
dyestuff  added,  and  this  will  represent  the  amount  originally 
absorbed  from  the  first  bath.  For  example:  it  required  the 
further  addition  of  2.5  per  cent,  of  Acid  Violet  to  match  the  second 
dyeing  to  the  first;  hence,  the  degree  of  exhaustion  would  be 
2-5  "*•  3  X  IO°  =  83-3  per  cent.,  which  is  a  rather  close  approxi- 
mation to  the  result  obtained  by  the  first  method.  The  first 
method  is  the  more  accurate,  but  in  some  cases  the  bath  after 
dyeing  has  a  different  color  from  that  of  starting,  and,  again,  some 
dyes  (mordant  colors)  give  solutions  which  do  not  accurately 
represent  the  color  obtained  by  dyeing;  in  which  cases  the 
latter  method  only  could  be  used. 

Experiment  162.  To  Determine  the  Correct  Amount  of  Mor- 
dant to  Use.  —  Mordant  six  test-skeins  of  woolen  yarn  each  with 
4  per  cent,  of  tartar  and  the  following  amounts  of  chrome: 


288  DYEING  AND    TEXTILE   CHEMISTRY. 

(1)  i  per  cent.  (445).  (4)     5  per  cent.  (448). 

(2)  2  per  cent.  (446).  (5)     8  per  cent.  (449). 

(3)  3  per  cent.  (447).  (6)    12  per  cent.  (450). 

Enter  at  140°  F.,  raise  to  boiling,  and  mordant  for  45  minutes; 
wash,  and  dye  the  skeins  all  together  with  3  per  cent,  of  Alizarin 
Red  in  the  usual  manner.  Rinse  and  dry.  Compare  the  several 
skeins,  and  by  selecting  the  best  color  thus  determine  which 
percentage  of  chrome  is  the  proper  one  to  use.  For  nearly  all 
purposes  of  mordanting  it  has  been  found  that  about  3  per  cent, 
of  chrome  gives  the  best  results.  A  larger  amount  of  chrome 
appears  to  oxidize  the  wool  and  cause  bad  shades  in  dyeing; 
this  is  known  as  over-chroming  and  the  wool  becomes  harsh 
and  brittle. 

Experiment  163.  To  Determine  the  Degree  of  Exhaustion  of 
the  Mordant  Bath.  —  Mordant  a  test-skein  of  woolen  yarn  in  a 
bath  containing  300  cc.  of  water,  3  per  cent,  of  chrome,  4  per  cent. 
of  tartar.  Enter  at  140°  F.,  raise  to  boiling,  and  mordant  for 
45  minutes.  Squeeze  back  the  liquor  from  the  skein  into  the 
bath  and  wash  well.  Add  sufficient  water  to  the  mordant  bath  to 
bring  its  volume  up  to  300  cc.  again,  and  without  further  addi- 
tions, mordant  a  second  skein  in  a  similar  manner.  Repeat  in 
the  same  way  with  a  third  skein.  Then  dye  the  three  skeins 
together  with  3  per  cent.  Alizarin  Red  in  the  usual  manner,  and 
finally  compare  the  skeins  for  depth .  of  shade  in  order  to  deter- 
mine the  relative  exhaustion  of  the  mordant  bath  (451,  452,  453). 

Repeat  this  test,  using  a  mordanting  bath  of  300  cc.  of  water, 
3  per  cent,  of  chrome,  2  per  cent,  of  lactic  acid,  2  per  cent,  of 
sulphuric  acid.  Mordant  three  test-skeins  successively  in  the 
manner  above  described  and  dye  again  with  3  per  cent,  of  Alizarin 
Red.  Compare  these  (454,  455, 456)  for  depth  of  shade  to  deter- 
mine the  relative  exhaustion  of  the  bath  and  also  to  determine  if 
the  exhaustion  is  the  same  in  the  second  case  as  in  the  first. 

Experiment  164.  To  Show  the  Dichroic  Property  of  a  Dyestuff. 
—  Coloring-matters  are  known  as  "dichroic"  when  they  change 
their  tone  with  change  of  intensity.  Magenta,  for  instance,  in 


MISCELLANEOUS   TESTS  IN  DYEING.  289 

heavy  shades  is  a  red  color,  while  in  light  tints  it  changes  to  a 
bluish  pink.  To  show  this  property  proceed  as  follows:  Dye 
six  tests  of  woolen  yarn  with  Magenta,  using  10  per  cent,  of  glau- 
bersalt  in  each  dye-bath  together  with  the  following  amounts  of 
dyestuff : 

(1)  3  per  cent.    (45?)  (4)  0.5    per  cent.   (460) 

(2)  2  per  cent.   (458)  (5)  o.i    percent.   (461) 

(3)  i  per  cent.    (459)  (6)  o.oi  per  cent.   (462) 

Enter  at  100°  F.,  raise  to  180°  F.,  and  dye  for  30  minutes. 
Observe  the  different  tones  in  the  colors  obtained  with  change  of 
concentration. 

The  dichroic  nature  of  a  coloring-matter  may  also  be  observed 
with  its  solution.  Take  a  small  quantity  of  Magenta  and  dissolve 
in  5  cc.  of  water  in  a  test-tube;  pour  out  half  of  this  solution  into 
a  second  test-tube  and  dilute  with  an  equal  quantity  of  water. 
Pour  out  half  of  the  second  solution  into  a  third  test-tube,  and 
dilute  again  with  four  times  the  amount  of  water.  Compare  the 
colors  of  the  three  solutions,  and  notice  the  effect  of  dilution  on 
the  tone  of  the  original  color.  In  the  same  manner  test  the 
dichroic  properties  of  Eosin,  Methyl  Violet,  and  Malachite  Green. 

Experiment  165.  Effect  of  Dichroism  in  the  Compounding  of 
Shades.  —  Dye  a  test-skein  of  woolen  yarn  with  3  per  cent,  of 
Auramine  (463),  and  another  with  3  per  cent,  of  Magenta  (464). 
Then  dye  two  more  skeins,  the  one  with  TV  per  cent,  of  Aura- 
mine  (465),  and  the  other  with  yV  per  cent,  of  Magenta  (466). 
Notice  that  the  Auramine  is  not  especially  dichroic,  whereas  the 
Magenta  is  markedly  so.  Now  dye  a  skein  (467)  with  a  mixture 
of  2  per  cent,  of  Auramine  and  3  per  cent,  of  Magenta  and  another 
skein  (468),  with  2  per  cent,  of  Auramine  and  i  per  cent,  of 
Magenta  and  a  third  skein  (469)  with  2  per  cent,  of  Auramine  and 
T<F  per  cent,  of  Magenta.  Notice  the  wide  difference  in  the 
character  of  the  colors  obtained;  for  while  the  Magenta  in  the  first 
case  (3  per  cent.)  exercises  the  function  of  a  red  dye,  in  the  last  case 
(TV  per  cent.)  it  acts  as  a  violet  dyestuff;  hence  the  effect 
is  entirely  different  in  kind.  Next  dye  a  skein  (470)  with 


290  DYEING  AND    TEXTILE   CHEMISTRY. 

^  per  cent,  of  Auramine  and  TV  per  cent,  of  Magenta,  and 
another  skein  (471)  with  2  per  cent,  of  Auramine  and  2  per  cent, 
of  Magenta.  Theoretically,  the  first  color  should  be  a  reduced 
tint  of  the  second;  but  practically  it  will  be  seen  that  the  two 
colors  are  of  entirely  different  orders.  This  is  caused  by  the 
wide  variation  in  the  color  of  the  Magenta  with  different  concen- 
trations. From  this  it  will  be  seen  that  the  dichroic  property  of 
a  dyestuff  has  an  important  bearing  on  its  mixing  qualities  with 
other  dyes  in  the  compounding  of  shades.  A  red  and  a  blue  dye 
when  used  together  in  heavy  shades  may  give  a  very  satisfactory 
violet;  but  if  the  attempt  is  made  to  obtain  a  reduced  tint  of  this 
violet  by  using  small  percentages  of  the  two  colors  in  the  same 
proportions,  it  will  perhaps  be  found  that  a  tint  of  an  entirely 
different  color  is  obtained.  The  same  is  true  when  dealing  with 
green  and  orange  colors.  In  order  to  become  acquainted  with 
the  true  mixing  qualities  of  his  dyestuffs,  the  dyer  should  be 
familiar  with  the  colors  they  give  with  large,  medium  and  small 
percentages,  and  in  the  mixing  of  his  shades  he  must  make  due 
allowance  for  the  change  in  tone  of  color  of  the  dyes  with  varying 
concentration. 

SAMPLES. 

436.  With  i  per  cent,  of  dyestuff. 

437.  With  2  per  cent,  of  dyestuff. 

438.  With  3  per  cent,  of  dyestuff. 

439.  With  4  per  cent,  of  dyestuff. 

440.  With  5  per  cent,  of  dyestuff. 

441.  With  6  per  cent,  of  dyestuff. 

442.  Dyeing  representing  first  bath. 

443.  Dyeing  from  exhausted  bath. 

444.  Second  dyeing  matched  to  first. 
445-  With  i  per  cent,  of  mordant. 
446.  With  2  per  cent,  of  mordant. 
447-  With  3  per  cent,  of  mordant. 

448.  With  5  per  cent,  of  mordant. 

449.  With  8  per  cent,  of  mordant. 

450.  With  12  per  cent,  of  mordant. 
45*.  Representing  first  bath  of  mordant. 

452 .   Representing  first  exhaustion  of  mordant. 


MISCELLANEOUS   TESTS  IN  DYEING.  29 1 

453.  Representing  second  exhaustion  of  mordant. 

454.  First  mordant  bath  with  lactic  acid. 

455.  First  exhaustion  with  lactic  acid. 

456.  Second  exhaustion  with  lactic  acid. 
457-462.  Dichroic  property  of  Magenta. 

463.  Dyeing  with  3  per  cent.  Auramine. 

464.  Dyeing  with  3  per  cent.  Magenta. 

465.  Dyeing  with  TO  per  cent.  Auramine. 

466.  Dyeing  with  TV  per  cent.  Magenta. 

467.  Dyeing  with  2  per  cent.  Auramine  and  3  per  cent.  Magenta. 

468.  Dyeing  with  2  per  cent.  Auramine  and  i  per  cent.  Magenta. 

469.  Dyeing  with  2  per  cent.  Auramine  and  £5  per  cent.  Magenta. 

470.  Dyeing  with  &  per  cent.  Auramine  and  rft  per  cent.  Magenta. 

471.  Dyeing  with  2  per  cent.  Auramine  and  2  per  cent.  Magenta. 

QUIZ  25. 

709.  How  would  you  determine  the  amount  of  dyestuff  required  to  yield  a 
full  shade  of  color?    What  percentage  of  Acid  Violet  gives  a  satisfactory  full 
shade  ? 

710.  What  is  meant  by  the  degree  of  exhaustion  of  the  dye-bath?     How 
may  this  be  determined  ?     Give  two  methods. 

711.  If  on  a  2  per  cent,  dyeing  for  first  bath  it  required  1.6  per  cent,  of  dye 
for  the  second  bath,  what  was  the  degree  of  exhaustion  ? 

712.  Describe  the  test  to  determine  the  correct  amount  of  mordant  to  use. 
What  percentage  of  chrome  gave  the  best  mordanting? 

713.  How  may  the  degree  of  exhaustion  of  the  mordant  bath  be  deter- 
mined ?     How  does  this  compare  for  tartar  and  lactic  acid  assistants  ? 

714.  What  is  meant  by  the  dichroic  property  of  a  dyestuff?    What  is  the 
dichroism  exhibited  by  Magenta  ? 

715.  How  would  you  determine  the  dichroism  of  a  dyestuff?    What  did 
you  observe  in  the  cases  of  Eosin,  Methyl  Violet,  and  Malachite  Green  ? 

716.  What  is  the  general  effect  of  dichroism  in  the  compounding  of  colors? 
How  may  this  be  shown  ? 


SECTION  XXVI. 

TESTING  THE  FASTNESS  OF  COLORS. 

IN  Section  IX,  brief  methods  have  already  been  given  for  the 
testing  of  dyed  colors  to  various  agencies.  The  present  section 
is  intended  to  be  a  more  extended  discussion  of  this  subject. 

By  the  "fastness"  of  a  dye  is  meant  its  resistance  to  the  action 
of  various  agencies  to  change  it  in  color  or  appearance.  The 
fastness  of  dyes  differs  very  widely  even  among  the  same  class; 
some  acid  dyes,  for  instance,  are  very  fast  while  others  are  fugi- 
tive; and  the  same  is  true  in  general  of  the  basic  and  substantive 
dyes.  The  mordant  dyes  are  to  be  regarded  as  having  the  great- 
est fastness  when  taken  as  a  class;  and  the  basic  dyes,  as  a  class, 
are  probably  the  most  fugitive.  Again,  dyes  may  be  fast  to  one 
agency  and  not  to  others;  for  instance,  Thioflavin  T  dyed  on 
cotton  is  very  fast  to  washing  and  to  fulling,  but  not  at  all  fast 
to  light.  Further,  a  dye  may  be  fast  on  one  fibre  and  not  on 
another;  and  may  be  fast  when  dyed  by  one  method  (or  mordant) 
and  not  fast  when  dyed  by  another  method  (or  mordant). 

Experiment  166.   Testing  Fastness  of  Colors  Dyed  on  Wool.  - 
The  chief  agencies  to  which  colors  on  wool  are  tested,  together 
with  the  means  of  so  testing  them,  are  as  follows: 

(i)  Fastness  to  Light.  —  A  sample  of  the  dyed  wool  is  placed 
in  a  suitable  frame  in  such  a  manner  that  only  a  part  is  exposed. 
The  frame  is  then  placed  in  such  a  position  that  it  receives  as 
strong  sunlight  as  possible,  but  is  shielded  from  exposure  to  the 
atmosphere  by  glass.  A  window  with  southern  exposure  is  a  good 
location  in  which  to  hang  the  frame  containing  the  samples.  At 
the  end  of  one  week's  exposure  the  samples  are  examined  and 
note  made  of  those  which  show  any  appreciable  fading;  these  are 
to  be  classified  as  not  fast.  At  the  end  of  the  second  week 
another  examination  is  made  and  those  samples  noted  which 

292 


TESTING    THE  FASTNESS  OF  COLORS.  293 

show  an  appreciable  fading;  these  are  to  be  classified  as  fairly 
fast.  At  the  end  of  four  weeks  the  samples  are  once  more 
examined  and  the  colors  fading  in  this  period  are  noted  and 
classified  as  fast.  The  samples  which  show  no  fading  at  the  end 
of  four  weeks  are  classified  as  very  fast. 

Dye  test-skeins  of  woolen  yarn  with  2  per  cent,  each  of  the  ten 
following  dyes,  and  test  samples  of  the  colors  for  fastness  to  light 
in  the  manner  above  described. 

1.  Magenta  (in  neutral  bath). 

2.  Eosin  (in  acetic  acid  bath). 

3.  Acid  Violet  (in  usual  acid  bath). 

4.  Tartrazin  (in  usual  acid  bath). 

5.  Patent  Blue  V  (in  usual  acid  bath). 

6.  Light  Green  SF  (in  usual  acid  bath). 

7.  Diamine  Scarlet  36  (ammonium  acetate  bath). 

8.  Cloth  Red  GA  (acid  bath  and  after-chromed). 

9.  Alizarin  Red  WS  (on  alum  mordant). 
10.  Alizarin  Blue  NG  (on  chrome  mordant). 

In  making  the  test  for  fastness  to  light,  as  the  nature  and 
amount  of  sunlight  obtainable  day  by  day  is  very  variable,  a 
more  accurate  method  is  to  expose,  with  the  samples  to  be 
tested,  control  samples  of  dyes  representing  the  four  degrees  of 
fastness  to  light,  such  as: 

1.  Very  fast,  Alizarin  Red  WS  (on  a  chrome  mordant). 

2.  Fast,  Lanacyl  Blue  R  (in  usual  acid  bath). 

3.  Fairly  fast,  Alkali  Blue  R  (in  neutral  bath  and  developed 
with  acid). 

4.  Eosin  (in  weak  acetic  acid  bath). 

The  samples  are  examined  from  time  to  time,  and  those  colors 
fading  in  the  same  periods  as  the  control  samples  are  noted  and 
classified  accordingly.  In  this  manner  the  variable  effect  due 
to  the  inconstant  degree  of  light  is  eliminated,  and  the  tests 
made  comparable  to  certain  fixed  standards. 

(2)  Fastness  to  Washing.  —  This  test  is  to  represent  the 
fastness  of  a  dye  to  washing  or  scouring  with  soap  and  water. 


294  DYEING   AND    TEXTILE   CHEMISTRY. 

Dyed  woolen  material  of  almost  any  character  should  be  capable 
of  standing  a  more  or  less  severe  scouring,  as  such  an  operation 
is  always  necessary  in  the  cleansing  and  finishing  of  woolen  goods 
in  the  course  of  their  manufacture.  Material  dyed  as  loose 
stock  must  afterwards  stand  a  rather  severe  scouring  in  order  to 
remove  the  oils  added  for  purposes  of  spinning;  yarn-dyed 
material  also  accumulates  considerable  grease  and  dirt  in  handling 
and  weaving  and  must  also  be  scoured.  Goods  dyed  in  the  piece 
are  usually  scoured  before  dyeing;  hence  colors  in  this  latter 
case  need  not  be  especially  fast  to  scouring,  unless  the  character 
of  the  goods  requires  them  to  be  subsequently  scoured  either  in 
manufacturing  or  in  wearing.  The  best  manner  of  conducting 
the  washing  or  scouring  test  is  as  follows:  Plait  together  a  few 
strands  of  the  dyed  test-skein  with  an  equal  portion  of  white  wool 
yarn  and  white  cotton  yarn.  Scour  this  sample  for  10  minutes 
in  a  miniature  scouring  bath  (about  50  cc.)  containing  5  grams 
of  soap  per  litre  at  a  temperature  of  140°  F.  Squeeze,  wash  off 
in  fresh  water,  and  dry.  Note  if  the  dye  tints  the  soap  solution, 
and  if  it  tints  either  the  white  wool  or  the  white  cotton.  The 
latter  is  used  in  the  test  as  cotton  threads  are  frequently  employed 
in  the  weaving  of  woolen  goods.  Some  dyes  may  tint  the  soap 
solution  without  staining  the  white  yarns,  but  this  may  result  in 
the  staining  of  other  colors,  hence  such  dyes  cannot  be  considered 
fast;  again,  some  dyes  may  stain  the  white  wool,  and  not  the 
white  cotton,  or  vice  versa;  in  either  case,  the  color  must  be 
classed  as  not  fast.  As  to  degrees  of  fastness,  an  arbitrary 
classification  may  be  made  as  follows : 

1.  Fast;  does  not  tint  the  soap  liquor,  nor  either  of  the  white 
yarns. 

2.  Fairly  fast;  tints  the  soap  liquor,  but  not  the  white  yarns. 

3.  Not  fast;  tints  either  of  the  white  yarns;  the  soap  liquor 
may  or  may  not  be  tinted. 

Make  up  plaited  test  samples  from  each  of  the  ten  colors  given 
above,  and  test  them  to  fastness  to  washing  in  the  manner  de- 
scribed; it  is  needless  to  add  that  a  fresh  portion  of  soap  liquor 
must  be  used  for  each  sample  tested. 


TESTING   THE  FASTNESS  OF   COLORS.  295 

(3)  Fastness  to  Fulling.  —  This  is  also  called  milling,   and 
refers  to  the  process  whereby  woolen  cloth  is  felted  more  or  less  in 
order  to  make  a  denser  fabric  or  to  otherwise  finish  the  goods. 
The  felting  is  carried  out  in  fulling  mills  or  stocks,  in  which  the 
material  is  saturated  usually  with  an  alkaline  soap  liquor  and  then 
rubbed  and  squeezed  together  until  the  desired  degree  of  felting 
is  obtained.     The  process  of  fulling  is  a  very  severe  test  on  colors, 
and  the  mordant  dyes  are  about  the  only  ones  which  will  stand 
a  hard  fulling;  there  are,  however,  certain  acid  and  substantive 
colors  on  wool  which  will  stand  a  fair  degree  of  fulling.     The 
basic  dyes  will  not  stand  fulling. 

The  fulling  test  may  best  be  carried  out  as  follows: 
Make  a  loose  plait  containing  several  strands  of  the  dyed  yarn 
mixed  with  strands  of  white  woolen  and  cotton  yarns,  and  treat 
with  a  solution  containing  10  grams  of  soap  and  2  grams  of  soda 
ash  per  litre  at  140°  F.  Soak  the  sample  in  this  solution  and  rub 
between  two  pieces  of  board  until  the  wool  yarns  are  well  felted 
together.  Then  wash  in  fresh  water,  and  dry.  Note  if  the  color 
has  lost  in  intensity  or  if  it  has  bled  into  either  the  white  wool 
or  cotton.  In  such  case  the  dye  cannot  be  considered  fast  to 
fulling.  According  to  the  degree  of  bleeding,  the  color  may  be 
classed  as  not  fast  or  as  fairly  fast.  If  the  dye  neither  loses  in 
color  nor  bleeds,  it  may  be  classed  as  fast.  Prepare  test  samples 
from  each  of  the  ten  dyes  given  and  test  them  in  manner  de- 
scribed for  fastness  to  fulling. 

(4)  Fastness  to  Rubbing.  —  This  is  also  termed  "  crocking," 
and  refers  to  whether  or  not  the  dye  will  mechanically  rub  off,  and 
thus  stain  white  or  other  colors  with  which  it  may  come  in  contact. 
Heavy  shades  are  more  apt  to  rub  than  light  shades.     As  a  rule, 
the  acid  and  substantive  dyes  on  wool  do  not  rub;  the  basic  dyes 
frequently  show  this  defect;  heavy  shades  of  mordant   (or  pig- 
ment dyes  in  general)   will  frequently  rub  off  to  some  extent, 
whereas  lighter   shades  do   not.     Heavy   shades   of   indigo    (a 
pigment  dye),  for  instance,  rub  off  considerably.     The  test  for 
fastness  to  rubbing  is  easily  and  simply  carried  out  by  rubbing 
a  portion  of  the  dyed  sample  on  a  piece  of  white  calico,  and 


296  DYEING  AND    TEXTILE  CHEMISTRY. 

noting  if  a  stain  is  left.     Test  the  ten  dyed  samples  in  this  manner, 
and  classify  as  fast  or  not  fast  to  rubbing. 

(5)  Fastness  to  Water.  —  The  object  of   this  is   to  discover 
if  the  dye  will  bleed  into  white  yarn  on  boiling  in  water  or  on  pro- 
longed   steeping    in    cold    water.     Test    as    follows:    (a)  Plait 
several  strands  of  the  dyed  yarn  with  some  white  wool  and  white 
cotton  yarns,  and  boil  with  water  for  i  hour.     Squeeze  and  dry. 
Note   if    the    white   yarns   become    stained,     (b)  Use    another 
plaited  sample  as  above,  and  steep  in  cold  water  for  12  hours. 
Note  if  the  white  yarns  become  stained.     If  the  dye  does  not 
bleed  at  all  in  boiling  water  it  may  be  classed  as  fast;  if  it  bleeds 
slightly  in  boiling  water,  but  not  in  cold  water,  it  is  fairly  fast; 
and  if  it  bleeds  in  the  cold  water  test,  it  is  not  fast.     Carry  out 
tests  on  the  ten  dyed  samples  in  the  manner  described,  and 
classify  these  dyes  with  respect  to  their  fastness  to  water. 

(6)  Fastness  to  Weather.  —  By  this  is  meant  fastness  to  the 
varying  conditions  of  exposure  to  the  atmosphere,  such  as  alter- 
nate wetting  by  rain  or  dew  and  drying  by  the  heat  of  the  sun,  etc. 
The  best  and  most  practical  method  of  applying  this  test  is  to 
expose  a  sample  of  the  dyed  material  to  the  action  of  the  weather 
for  two  weeks  or  more.     But  the  results  may  be  approximately 
represented  by  the  following  test,     (a)  Steep  a  sample  of  the 
dyed  yarn  in  a  solution  containing  2  parts  of  hydrogen  peroxide 
(lo-volume  strength)  and  10  parts  of  water  for  i  hour.     Dry 
and  compare  with  the  original  sample,     (b)  Repeat  the  test, 
using  a  hydrogen  peroxide  solution  of  10- volume  strength  undi- 
luted with  water;  steep  for  i  hour,  and  on  drying  compare  with 
the  original  sample.     If  no  alteration  in  the  color  is  appreciable 
after  test  (6),  the  dye  may  be  classed  as /as/;  if  test  (b)  shows  an 
alteration  in  the  color,  but  not  test  (a) ,  the  dye  may  be  classed  as 
fairly  fast;  if  test  (a)  shows  an  appreciable  alteration,  the  dye  is 
not  fast.     By  combining  this  test  with  the  one  to  sunlight,  a  fair 
idea  of  the  fastness  of  the  dye  to  weather  exposure  may  be  gained. 
It  is  probable  that  in  the  wetting  of  material  by  rain  or  dew  and 
subsequent  evaporation  by  the  heat  of  the  sun,  a  trace  of  hydro- 
gen peroxide  is  formed  which  has  a  bleaching  action  on  colors. 


TESTING   THE  FASTNESS  OF  COLORS.  297 

(7)  Fastness  to  Acids  and  Carbonizing.  —  In  many  cases  dyed 
woolen  materials  are  treated  with  moderately  strong  solutions  of 
acids  and  dried  in  order  to  decompose  any  particles  of  vegetable 
matter  which  may  be  present;  this  process  is  known  as  carboniz- 
ing.    To  test  the  fastness  of  a  dyestuff  to  this  operation,  proceed 
as   follows:  Immerse   a  sample  of  the  dyed  yarn   in  a   solu- 
tion of  sulphuric  acid  of  4°  Tw.  at  175°  F.  for  half  an  hour; 
squeeze   and   without   washing   dry  in   a   hot   air    flue.     Then 
wash  out  and  neutralize  the  acid  in  a  bath  containing  about 
-i  gram  of  soda  ash  to  100  cc.  of  water;  finally  rinse  well,  and 
dry.     Compare  with   the  original   color,    and   note  if  the  car- 
bonizing process  has  altered  the  shade  in  any  manner.     Accord- 
ing to  the  extent  of  change  in  the  shade  classify  as  not   fast, 
fairly  fast,  and  fast.     Test  in  this  manner  each  of  the  ten  dyed 
samples. 

(8)  Fastness  to  Perspiration.  —  This  is  required  of  all  dyed 
clothing  material  that  is  worn  next  the  skin;  also  of  material  used 
for  making  horse-blankets,  etc.     The  most  reliable  test  is  to 
wear  a  sample  of  the  dyed  wool  in  such  a  manner  as  to  expose 
it  to  the  action  of  perspiration.      This  action,  however,  may 
be  well  represented  by  the  following  test:  Plait  a  sample  of  the 
dyed  yarn  with  white  woolen  and  cotton  yarns,  and  immerse  for 
i  hour  in  a  solution  of  acetic  acid  of  4°  Tw.  at  100°  F.    Squeeze, 
and  dry  without  washing  in  the  air.    Note  if  the  color  has  suffered 
any  alteration  in  shade  or  if  it  has  stained  either  of  the  white 
yarns.     According  to  the  extent  of  change  or  staining  classify  as 
not  fast,  fairly  fast,  or  fast. 

(9)  Fastness  to  Alkali.  —  In  order  to  remove  the  fatty  matters 
from  woolen  goods  a  washing  with  dilute  soda  ash  solution  is 
frequently  given.     This  is  especially  true  of  material  which  is 
fulled.     To  discover  if  the  color  will  withstand  such  a  treatment, 
a  test  is  made  as  follows:  A  sample  of  the  dyed  yarn  is  plaited 
with  white  wool  and  white  cotton,  and  steeped  for  one  hour  in  a 
solution  of  soda  ash  of  3°  Tw.  at  i2o°F.,  then  washed  in  fresh 
water  and  dried.     Note  if  the  color  suffers  any  alteration,  or  if 
either  of  the  white  yarns  is  stained.     According  to  the  extent  of 


298  DYEING   AND    TEXTILE   CHEMISTRY. 

change  in  color  or  staining  the  dye  is  to  be  classified  as  not  fast, 
fairly  fast,  or  fast. 

(10)  Fastness  to  Lime  or  Street  Dust.  —  Dyed  clothing  materials 
such  as  ladies'  dress  goods  and  gentlemen's  suitings  have  to  with- 
stand the  action  of  street  dust,  mud,  etc.  This  action  is  best 
represented  by  a  test  with  lime  as  follows:  Spot  a  sample  of  the 
dyed  yarn  with  a  solution  containing  20  grams  quicklime  and 
10  cc.  ammonia  per  litre.  Allow  this  to  dry  on  the  material,  and 
then  brush  off.  Note  if  the  color  has  suffered  any  alteration. 

(n)  Fastness  to  Sulphuring  or  Staving.  —  In  some  cases  dyed 
woolen  yarn  is  woven  together  with  white  and  the  cloth  subse- 
quently bleached  by  the  action  of  sulphurous  acid  gas.  To  dis- 
cover if  the  dye  will  withstand  the  action  of  the  sulphurous  acid 
test  as  follows:  Take  a  small  sample  of  the  dyed  yarn,  moisten  it 
with  water,  and  hang  it  for  6  hours  in  a  closed  bottle  filled  with 
sulphurous  acid  gas  (obtained  by  burning  a  piece  of  sulphur  in 
the  bottle) .  Note  if  the  color  undergoes  any  alteration,  and  cor- 
responding to  the  extent  of  change  classify  the  dye  as  not  fast, 
fairly  fast,  or  fast. 

(12)  Fastness  to  Steaming.  —  In  the  various  finishing  opera- 
tions, dyed  woolen  fabrics  may  be  subjected  to  a  steaming  opera- 
tion in  order  to  give  the  surface  of  the  goods  a  lustre  and  a  certain 
finish.     This  process  is  frequently  called  "decatizing"  or  "  pott- 
ing."    The  same  operation  is  carried  out  on  goods  composed  of 
wool  and  cotton  yarns  in  order  to  prevent  crinkling,  in  which  case 
it  is  called  "crabbing."     To  test  a  dyestuff  to  the  influence  of 
such  an  operation  proceed  as  follows:  Prepare  a  plaited  sample 
containing  the  dyed  yarn  together  with  white  wool  and  cotton. 
Steam  the  sample  for  one-half  hour  under  about  5  pounds  pressure. 
Note  if  the  color  suffers  any  alteration,  or  if  it  stains  the  white 
yarns.     According  to  the  extent  of  change  or  staining  classify  the 
dye  as  not  fast,  fairly  fast,  or  fast. 

(13)  Fastness  to  Hot  Pressing  or  Ironing.  —  Woolen  material 
employed  in  the  manufacture  of  suitings,  etc.,  requires  to  be  hot 
pressed  or  ironed.     To  discover  if  a  dyestuff  will  withstand  such 
a  treatment,  test  as  follows:  (a)  *  Moisten  a  sample  of  the  dyed 


TESTING   THE  FASTNESS  OF  COLORS.  299 

yarn  and  press  with  a  hot  iron  till  dry.  Note  if  the  color  undergoes 
any  alteration  on  cooling,  (b)  Moisten  a  sample  of  the  dyed 
yarn  and  cover  with  a  piece  of  white  muslin,  then  press  with  a 
hot  iron  until  dry.  Note  if  the  color  suffers  any  alteration  or  if 
it  stains  the  white  muslin.  If  no  change  takes  place  under  (a) 
class  the  dye  as  fast ;  if  it  changes  under  (a)  but  not  under  (b) ,  or 
stains  the  white  slightly  without  any  other  perceptible  change, 
class  as  fairly  fast ;  if  the  color  is  altered  by  both  (a)  and  (b)  class 
as  not  fast. 

Experiment  167.  Testing  the  Fastness  of  Cotton  Dyeings.  — 
In  many  cases  dyeings  on  cotton  materials  are  tested  in  the  same 
manner  as  on  wool;  but  there  are  deviations  from  the  latter, 
owing  to  the  different  character  of  the  fibre.  The  following  are 
the  chief  tests  to  be  applied  to  dyed  cotton  material: 

(1)  Fastness  to  Light.  —  Tested  in  the  same  manner  as  with 
wool. 

(2)  Fastness  to  Washing.  —  Tested  in  the  same  manner  as 
with  wool. 

(3)  Fastness  to  Fulling.  —  Tested  in  the   same   manner   as 
with  wool. 

(4)  Fastness  to  Rubbing.  —  Tested  in  the  same  manner  as 
with  wool. 

(5)  Fastness  to  Water.  —  Tested  in  the  same  manner  as  with 
wool. 

(6)  Fastness  to  Acid.  —  It  is  frequently  the  practice  to  weave 
dyed  cotton  yarn  with  white  wool  and  subsequently  to  dye  the 
wool  with  acid  colors.     This  is  termed  " cross-dyeing."     To  dis- 
cover if  the  dyed  cotton  will  withstand  the  action  of  the  boiling  acid 
dye-bath,  test  as  follows:  Plait  a  sample  of  the  dyed  yarn  with 
white  wool  and  cotton,  and  boil  for  i  hour  in  a  solution  contain- 
ing i  cc.  sulphuric  acid  and  2.5  grams  glaubersalt  per  litre.    Then 
wash  and  dry.     Note  if  the  color  sustains  any  alteration  or  if  it 
bleeds  into  the  white  yarns,  and  classify  the  dye  as  not  fast, 
fairly  fast,  or  fast. 

(7)  Fastness  to  Weather.  —  Tested  with  hydrogen  peroxide  in 
the  same  manner  as  with  wool. 


300  DYEING   AND    TEXTILE   CHEMISTRY. 

(8)  Fastness  to  Perspiration.  —  Tested  with  acetic  acid  in  the 
same  manner  as  with  wool. 

(9)  Fastness  to  Alkali.  —  This  is  tested  in  the  following  man- 
ner: (a)  Steep  a  sample  of  the  dyed  yarn  for  2  minutes  in  cold 
ammonia  water  (full  strength),  and  observe  if  the  color  undergoes 
any  alteration,     (b)  Steep  a  similar  sample  in  a  solution  containing 
10  grams  of  soda  ash  to  100  cc.  of  water  for  2  minutes,  and  dry 
without  washing.     Note  if  the  color  undergoes  any  alteration. 
(c)  Plait  a  sample  of  the  dyed  yarn  with  white  wool  and  cotton, 
and  boil  for  one-half  hour  in  a  solution  containing  2  grams  of 
soda  ash  per  litre;  rinse  and  dry.     Observe  if  the  color  suffers  any 
change,  and  if  the  white  yarns  become  tinted.     From  these  tests 
classify  the  color  as  fast,  fairly  fast,  or  not  fast. 

(10)  Fastness  to  Mercerizing.  —  In  some  cases  cotton  is  mer- 
cerized after  being  dyed;  and  as  the  mercerizing  process  consists 
in  treating  the  material  with  strong  solutions  of  caustic  soda,  it  is 
necessary  that  the  dyed  color  should  not  be  affected  by  this  treat- 
ment in  order  to  be  employed  on  this  class  of  material.     Carry 
out  the  test  as  follows:  Steep  a  sample  of  the  dyed  yarn  in  a 
solution  of  caustic  soda  of  50°  Tw.  for  5  minutes;  wash  well  in 
cold  water,  then  in  hot  water,  and  finally  in  water  acidulated  with 
acetic  acid;  dry,  and  observe  if  the  color  has  undergone  any 
alteration,  and  classify  accordingly  as  fast,  fairly  fast,  or  not 
fast. 

(n)  Fastness  to  Chlorine  or  Bleaching.  —  Cotton  fabrics  con- 
taining white  interwoven  with  colored  yarns  are  frequently 
bleached  more  or  less  thoroughly  in  order  to  clear  the  white;  such 
material  as  cotton  towelling  containing  colored  borders  is  also 
bleached  quite  thoroughly.  To  discover  if  a  dye  will  withstand 
the  action  of  bleaching  which  is  done  with  solutions  of  chloride  of 
lime,  the  following  test  should  be  made:  Steep  a  sample  of  the 
dyed  yarn  in  a  cold  solution  of  chloride  of  lime  of  i|°  Tw.  for 
i  hour.  Rinse  in  water  slightly  acidulated  with  hydrochloric 
acid,  then  in  dilute  soap  solution,  and  finally  dry.  Observe  if  the 
color  has  undergone  any  alteration  in  shade,  and  classify  accord- 
ingly as  fast,  fairly  fast,  and  not  fast. 


TESTING    THE  FASTNESS  OF  COLORS.  30 1 

(12)  Fastness  to  Lime  or  Street  Dust.  —  This  is  determined  in 
the  same  manner  as  with  wool. 

(13)  Fastness  to  Steaming.  —  This  is  determined  in  the  same 
manner  as  with  wool. 

(14)  Fastness  to  Ironing  or  Hot  Pressing.  —  This  is  deter- 
mined in  the  same  manner  as  with  wool. 

Dye  ten  test-skeins  of  cotton  with  2  per  cent,  of  the  following 
dyestuffs,  and  test  each  color  with  respect  to  fastness  to  the 
different  agencies  as  above  described: 

1.  Benzopurpurine  (substantive  dye). 

2.  Chrysophenine  (substantive  dye). 

3.  Diamine    Blue    RW    (substantive    dye    after-treated   with 
bluestone) . 

4.  Dianil  Direct  Yellow  S  (substantive  dye). 

5.  Dianil   Brown   3  GO    (substantive   dye    after-treated  with 
chrome) . 

6.  Methyl  Violet  (basic  dye  on  tannin-antimony  mordant). 

7.  Magenta  (basic  dye  on  tannin-antimony  mordant). 

8.  Methylene  Blue  (basic  dye  on  tannin-antimony  mordant). 

9.  Cotton  Blue  (acid  dye  on  "blue  mordant"). 

10.    Rhodamine  (basic  dye  on  oil-aluminium  mordant). 

TABULATION   OF  FASTNESS   REQUIRED   ON  VARIOUS   CLASSES 
OF  MATERIALS. 

(a)   Wool. 

(1)  Loose  Wool.  —  Fastness  to  light,  fulling,  and  potting;  the 
dyes  recommended  are  mordant  colors  first,  and  substantive  dyes 
next.     The  latter  are  quite  fast  to  scouring  on  wool,  and  fairly 
fast  to  fulling;  they  are  especially  recommended  for  dyeing  in 
machines  on  account  of  their  good  solubility. 

(2)  Shoddy,    Mungo,    and    Carbonized    Rags.  —  Fastness    to 
fulling   and  cheapness  in  dyeing;   fastness  to   light   is   seldom 
required.     The  dyes  recommended  are  the  mordant  and  sub- 
stantive colors  in  the  first  place,  and  secondly  the  basic  colors. 
The  latter  are  only  fast  to  very  light  fulling,  but  do  not  stain 
white  cotton,  and  are  valuable  on  account  of  their  great  brilliancy. 


302 


DYEING   AND    TEXTILE   CHEMISTRY. 


TESTING   THE  FASTNESS  OF   COLORS. 


303 


304  DYEING   AND    TEXTILE   CHEMISTRY. 

(3)  Stubbing  and  Tops.  —  The  fastness  required  and  the  dyes 
recommended  are  the  same  as  for  loose  wool. 

(4)  Weaving  Yarns  (Worsted,  Cheviot  and  Carded  Yarns).  — 
As  these  are  chiefly  used  for  scouring  and  fulling  purposes,  the 
fastness  required  and  the  dyes  recommended  are  the  same  as 
for  loose  wool. 

(5)  Worsted   Knitting    Yarns   and   Hosiery    Yarns.  —  These 
require  fastness  to  scouring,  perspiration,  and  rubbing.     Substan- 
tive and  mordant  dyes  are  recommended ;  also  the  faster  acid  dyes. 

(6)  Yarns  for  Flannels,  Rugs,  Blankets,  Plaids,  etc.  —  These 
require  a  moderate  fastness  to  fulling;  also  fastness  to  perspi- 
ration  and    rubbing,  and    for   rug   yarns  fastness  to  stoving  is 
frequently  desired.     Substantive  and  mordant  dyes  are  recom- 
mended as  well  as  the  faster  acid  colors,  especially  those  which 
are  after-treated. 

(7)  Carpet  and  Tapestry  Yarns.  —  These  require  fastness  to 
light,  cold  water,  and  rubbing;  dyes  possessed  of  good  levelling 
properties  are  also  desired.     The  best  dyes  are  acid  colors  fast 
to  light,  then  the  mordant  dyes,  and  the  substantive  dyes  which 
are  after-treated  with  bluestone. 

(8)  Worsted   Braids.  —  These   require    dyes    that    penetrate 
well,  and  that  are  fast  to  light  and  rubbing.     The  same  colors 
as  for  the  preceding  are  recommended. 

(9)  Fancy  Yarns.  —  Fastness  to  stoving   and  clear  brilliant 
colors  are  usually  desired.     The  best  dyes  to  use  are  the  level 
dyeing  acid  colors  and  the  basic  colors. 

(10)  Piece   Goods  consisting   of  Woolen  Cloths  (Beavers  and 
Meltons),    Gentlemen's    Suitings,    Worsted    Coatings,    Cheviots, 
Carded    Woolen    Cloths,    Braids  for   Army   and   Navy    Cloths, 
Billiard  Cloth.  —  In  such  goods  it  is  desirable  that  the  dyes  be 
level  and  penetrate  well;  fastness  to  light,  potting,  hot  pressing, 
and  rubbing  is   also   required,  and   in   some  cases,  fastness  to 
carbonizing.     The  dyes  best  to  use  are  the  faster  acid  colors  and 
the  mordant  colors,  and  secondly  the  substantive  dyes. 

(n)  Dress  Goods,  Ladies1  Cloths,  Dogskins,  Doeskins,  Cash- 
meres, Crepons,  etc.  —  These  require  the  same   fastness  as  the 


TESTING   THE  FASTNESS  OF  COLORS.  305 

preceding,  and  also  fastness  to  street  dust.     The  same  dyes  are 
used  as  with  the  preceding. 

(12)  Flannels.  —  These  principally  require  fastness  to  wash- 
ing and  light;  the  dyes  chiefly  used  are  the  acid  and  substantive 
colors,  the  latter  being  largely  employed  for  red  shades. 

(13)  Velvets  and  Plushes.  —  These  require  fastness  to  light 
and  rubbing;  acid  dyes  are  principally  used. 

(14)  Woolen  Felt.  —  Good  penetration    and  level   dyeing  is 
the  first  consideration;  the  fastness  required  will  vary  with  the 
particular  use  to  which  the  goods  are  put.     The  dyes  mostly 
used  are  the  easily  soluble  acid  colors  and  the  substantive  colors. 

(15)  Hats  of  Wool  and  Hair.  —  In  this  case  fastness  to  light, 
potting,  and  rubbing  is  required;  also  the  color  must  penetrate 
well.     The  dyes  principally  used  are  mordant  colors,  and  readily 
soluble  acid  colors  fast  to  light. 

(b)    Cotton. 

(1)  Loose  Cotton  and  Stubbing.  —  These  require  to  be  fast 
to    fulling    and   light,   though   the   requirements   vary   greatly, 
according  to  the  use  to  which  the  material  is  to  be  put.     The 
dyes  mostly  used  are  the  substantive  colors,  dyed  direct,  diazo- 
tized    and    developed,    or    after-treated;    also    substantive   dyes 
topped  with  basic  colors,  and  even  basic  colors  alone. 

(2)  Fancy  Weaving  Yarns,  Cotton  Warps  for  Union  Goods, 
Knitting  Yarns,  Hosiery  Yarns. — These  require  fastness  to  scour- 
ing (and  sometimes  fulling)  to  cross-dyeing,  to  light,  and  generally 
to  perspiration,  though  the  degree  of  fastness  will  necessarily  vary 
considerably  with  the  use  to  which  the  yarn  is  to  be  put.     The 
dyes  recommended  are  the  diazotized  and  developed  and  the 
after-treated  substantive  colors,  sulphur  colors,  basic  colors,  and 
substantive  colors  topped  with  basic;  for  light  shades,  the  direct 
dyed  substantive  colors.     For  cop  dyeing  the  substantive  colors 
of  ready  solublity  are  principally  used. 

(3)  Yarns  for  Draperies,  Upholstery,  etc.  —  These  chiefly  re- 
quire fastness  to  light  and  rubbing.    The  dyes  mostly  used  are  the 
substantive  colors,  the  basic  colors,  and  some  of  the  acid  colors. 


306  DYEING   AND    TEXTILE   CHEMISTRY. 

(4)  Sewing    Cotton.  —  This    requires    fastness    to    light    and 
rubbing.     The  substantive  and  basic  dyes  are  chiefly  used. 

(5)  Cotton  Hosiery  and  Knit  Goods.  —  These  require  fastness 
to  washing,  perspiration,  rubbing,  and  sometimes  light.     The 
dyes  must  also  penetrate  well.     The  colors  used  are  the  same 
as  for  knitting  yarns;  also  aniline  black  and  the  sulphur  colors. 

(6)  Piece    Goods   consisting   of  Moleskins,    Cotton    Worsteds, 
Beavers,  Fustians,  Flannelettes,  Sateens,  Plushes,   Velvets,  Cor- 
duroys,  etc.  —  These   usually  require   fastness   to   perspiration, 
light,  rubbing,  hot  pressing,  and  in  some  cases  also  fastness  to 
washing.     The  dyes  mostly  used  are  the  substantive  colors  dyed 
direct,  also   diazotized  and  developed,  and    after-treated;    also 
the  sulphur  dyes;  also  substantive  dyes  topped  with  basic  colors, 
and  at  times  basic  dyes  alone. 

(7)  Cotton  Linings,   Bobbinnet,    Tulle,   etc.  —  These   require 
fastness  to  rubbing,  perspiration,  and  frequently  hot  pressing. 
The   dyes  chiefly  used  are  the  substantive  colors  dyed  direct, 
diazotized  and  developed,  or  topped  with  basic  dyes;  the  sulphur 
dyes;    and   the   basic  dyes.     Bobbinnet  is  frequently   dyed  in 
the  sizing. 

(8)  Bookbinders1  Cloth.  —  About   the   only  fastness   required 
is  to  light.     The  dyeing  is  frequently  done  in  the  sizing,  using 
acid  dyes,  basic  dyes,  and  substantive  dyes. 

(c)    Union  Goods. 

(1)  Thread  Waste,  Shoddy,  etc.  —  Moderate  fastness  to  fulling 
is  usually  required   together  with  cheapness  of  dyeing.     The 
dyes  mostly  used  are  the  substantive  colors,  either  alone  or  in 
conjunction  with  neutral  dyeing  acid  colors;  also  after-treated 
substantive  colors. 

(2)  Merino-  and  Angola   Yarns,  Braids,  etc. —  The  require- 
ments for  fastness  vary  with  the  application.     The  dyes  used  are 
those    given    above,  also    substantive   dyes   topped    with    basic 
colors. 

(3)  Hosiery  Yarns.  —  These  require  fastness  to  perspiration, 
washing,  and  rubbing.  The  dyes  employed  are  those  given  above. 


TESTING   THE  FASTNESS  OF  COLORS.  307 

(4)  Piece  Goods  consisting  of  Cotton  Warp  Suitings,  Woolens, 
Dress  Goods,  Shawls,  Crewels,  Astrachans,  Italian  Cloth,  Serges, 
Hosiery,  Felt,  and  Flannels.  —  The  requirements  for  fastness 
vary  with  the  nature  and  use  of  the  material;  in  general,  fastness 
to  washing  and  rubbing  is  desired;  fastness  to  light  is  of  minor 
importance  with  linings  and  hosiery.     The  dyes  mostly  used  are 
the  substantive  dyes  either  alone  or  in  combination  with  the 
neutral  dyeing  acid  colors. 

(5)  Ladies'  Cloths,   Presidents,  Whitney s,  Moscows,  Beavers, 
Worsted   Coatings,   etc.  —  The   only   important   requirement   is 
sufficient  fastness  to  light,  water,  rubbing,  and  hot  pressing.     The 
dye  should  cover  the  cotton  well,  be  level  dyeing,  and  have  good 
penetration.     The  substantive  dyes  are  principally  used,  either 
alone  or  in  combination  with  neutral  dyeing  acid  colors. 

QUIZ  26. 

717.  What  is  meant  by  the  "fastness"  of  a  dyestuff?    Is  this  fastness  a 
constant  factor  among  different  dyes  of  the  same  class  ?    Which  class  of  dyes 
is  to  be  regarded  as  the  fastest  ?    Which  most  fugitive  ? 

718.  Does  the  same  dye  exhibit  the  same  degree  of  fastness  on  different 
fibres  ?     Have  different  methods  of  dyeing  any  influence  on  the  fastness  of  the 
colors  ? 

719.  What   are   the   agencies   to   which   dyes   on  woolen   materials   are 
tested? 

720.  Give  the  method  of  testing  fastness  to  light.     Should  exposure  to  the 
atmosphere  be  included  in  a  light  test,  and  why  ? 

72 1 .  Why  are  standards  used  in  making  the  light  test,  and  what  are  these 
standards  ? 

722.  What  does  the  washing  test  represent?    Is  woolen  material  always 
scoured  after  dyeing  ?    Which  class  of  goods  should  have  dyes  fast  to  washing, 
loose  stock,  yarn,  or  cloth  ? 

723.  Describe  the  washing  or  scouring  test.     Why  is  the  sample  mixed 
with  white  wool  and  cotton  ? 

724.  How  are  dyes  classified  as  to  degrees  of  fastness  to  washing  ? 

725.  What  is  meant  by  "fulling"?     By  what  other  term  is  it  known?     Is 
this  process  severe  on  colors?    Which  class  of  dyes  is  fastest  to  fulling? 

726.  Describe  the  method  of  testing  fastness  to  fulling. 

727.  What  is  meant  by  the  "crocking"  test?    How  is  it  carried  out? 

728.  What   is   understood   by   fastness  to   "water"?    How  is  the   test 
made? 


308  DYEING   AND    TEXTILE   CHEMISTRY. 

729.  What  is  meant  by  fastness  to  "weather"?    How  may  the  test  be 
represented  by  chemical  means  ?    With  what  other  test  should  this  always  be 
combined  ? 

730.  What  is  "carbonizing"?    How  is  the  test  made ? 

731.  Give  the  best  method  of  making  the  perspiration  test.     By  what 
chemical  test  may  it  be  represented  ? 

732.  In  what  case  is  a  treatment  with  alkali  given  dyed  woolen  fabrics? 
How  is  the  test  for  fastness  to  alkali  conducted  ? 

733.  How  is  fastness  to  street  dust  represented  by  chemical  means? 

734.  What  is  meant  by  "stoving"?     Under  what  circumstances  would  a 
color  be  required  to  stand  this  test  ?    How  is  the  test  for  fastness  made  ? 

735-  What  is  " decatizing, "  "crabbing"  ?     How  may  the  fastness  of  a  color 
to  steaming  be  tested  ? 

736.  The  colors  on  what  classes  of  materials  require  fastness  to  ironing  *or 
hot-pressing  ?    How  is  this  test  made  ? 

737.  In  what  respects  does  the  testing  of  dyed  colors  on  cotton  differ  from 
those  on  wool  ? 

738.  How  is  the  test  for  fastness  to  acid  carried  out?    What  is  meant  by 
"cross-dyeing"? 

739.  How  does  the  test  for  fastness  to  alkali  differ  on  woolen  and  on  cotton 
goods  ? 

740.  What  is  meant  by  "mercerizing"?    Under  what  conditions  would 
this  fastness  be  required,  and  how  is  the  test  made  ? 

741.  How  does  the  bleaching  test  for  cotton  colors  differ  from  that  of  stov- 
ing? 

742.  Referring  to  the  cotton  colors  tested,  how  do  the  basic  dyes  compare 
in  general  fastness  with  the  substantive  dyes?    In  what  particulars  do  the 
latter  surpass  the  basic  dyes? 

743.  What  fastness  is  required  on  loose  wool  dyeings,  and  what  are  the 
chief  classes  of  colors  used  on  this  material  ?    What  character  of  dyes  is  used 

or  machine  dyeing? 

744.  What  fastness  is  required  for  shoddy  dyeings?    Why  are  basic  dyes 
used  largely  ? 

745.  What  are  slubbing  and  tops?    What  fastness  is  required  for  these 
dyeings  ? 

746.  What  fastness  is  generally  necessary  for  worsted  and  woolen  weaving 
yarns  ?    What  dyes  are  mostly  used  ? 

747.  What  fastness  is  required  for  knitting  and  hosiery  yarns  of  wool? 
Yarns  for  rugs,  blankets,  and  flannels  ? 

748.  What  fastness  is  required  on  carpet  and  tapestry  yarns?     Yarns  for 
worsted  braid? 

749.  What  are  the  dyes  employed  for  woolen  piece  dyeings?    What  is 
meant  by  fastness  to  "potting"? 


TESTING   THE  FASTNESS  OF  COLORS.  309 

750.  What  fastness  is  required  on  ladies'  dress  goods?    What  is  the  chief 
fastness  for  flannels  ? 

751.  What  fastness  is  required  for  velvets  and  plushes?    What  dyes  are 
chiefly  used  ?    What  qualities  are  necessary  for  colors  on  woolen  felts  ? 

752.  What  fastness  is  required  on  loose  cotton  and  slubbing?     On  cotton 
warps  for  union  goods  ?     For  cotton  hosiery  yarns  ? 

753-   For  cop-dyed  cotton  yarns  what  colors  are  best  to  use  and  why? 

754.   Colors  on  cotton  draperies  and  upholstery  require  what  fastness? 
What  dyes  are  chiefly  used  on  sewing  cotton  ? 

755-  What  fastness  is  required  for  colors  on  the  general  class  of  cotton 
piece  goods  ?     Cotton  linings  ?    What  is  meant  by  dyeing  in  the  sizing  ? 

-756.   For  bookbinders'  cloth  what  fastness  is  desirable?      What  kind  of 
dyes  are  mostly  used  ? 

757.  What  are  "merino"  and  "angola"  yarns?    What  fastness  is  required 
on  these  ?    What  dyes  are  used  ? 

758.  Name  some  of  the  principal  varieties  of  union  clothing  material. 
What  fastness  is  desirable  for  such  colors  ? 


SECTION  XXVII. 
ANALYSIS  OF  TEXTILE  FABRICS. 

Experiment  168.  To  Determine  the  Amount  of  Wool  and 
Cotton  in  a  Fabric.  —  A  weighed  portion  of  the  sample  is  boiled 
for  10  minutes  in  a  5  per  cent,  solution  of  caustic  potash,  then 
washed  well  first  with  fresh  water  and  afterwards  with  water 
slightly  adiculated  with  acetic  acid  to  remove  all  trace  of  alkali. 
The  residue  is  dried  and  weighed.  As  the  wool  is  dissolved  by 
the  alkali,  the  loss  in  weight  corresponds  to  the  amount  of  wool, 
while  the  residue  represents  the  cotton.  Record  the  results  as 
in  the  following  example: 

Weight  of  sample 5.25  grams. 

After  boiling  in  caustic  potash 1.06  grams. 

Loss  equals  wool 4.19  grams. 

Residue  equals  cotton 1.06  grams. 


Hence:  Wool  =  79.8  per  cent. 

Cotton  =  20.2  per  cent. 


As  the  cotton  present  will  suffer  a  slight  loss  in  the  process,  it  is 
customary  to  add  5  per  cent,  of  its  weight  to  the  cotton,  and  to 
subtract  this  amount  from  that  of  the  wool.  With  this  correction 
the  above  figures  become: 


Wool  =  78.79  per  cent. 
Cotton  =  21.21  per  cent. 


Experiment  169.  Analysis  of  Fabric  Containing  Silk  and 
Cotton.  —  (a)  Nickel  Hydrate  Method.  A  weighed  portion  of 
the  fabric  (about  5  grams)  is  steeped  for  5  minutes  in  a  cold 
solution  of  nickel  hydrate  in  ammonia;  then  heated  almost  to 
boiling- for  5  minutes.  This  treatment  should  dissolve  the  silk 
completely.  The  residue  of  cotton  is  thoroughly  washed,  dried, 

310 


ANALYSIS   OF   TEXTILE  FABRICS.  311 

and  weighed.  The  nickel  hydrate  solution  for  this  test  is  pre- 
pared as  follows:  25  grams  of  crystallized  nickel  sulphate  are 
dissolved  in  500  cc.  of  water;  then  sufficient  caustic  soda  solution 
is  added  to  completely  precipitate  the  nickel  as  hydrate.  This 
precipitate  is  well  washed  with  water  by  settling  and  decantation, 
and  finally  rinsed  into  a  250  cc.  flask  with  125  cc.  of  water.  The 
flask  is  next  filled  with  ammonia  water  and  well  shaken,  and  the 
nickel  hydrate  should  finally  completely  dissolve. 

(b)  Zinc  Chloride  Method.  —  A  weighed  portion  of  the  sample 
is  boiled  for  2  minutes  in  a  solution  of  basic  zinc  chloride  of 
1.72  sp.  gr.  The  residue  of  cotton  is  thoroughly  washed  first 
with  dilute  hydrochloric  acid,  and  then  with  water,  and  then 
dried  and  weighed.  This  treatment  dissolves  the  silk  without 
materially  affecting  the  cotton.  The  basic  zinc  chloride  solution 
is  prepared  as  follows:  100  grams  of  zinc  chloride  and  4  grams  of 
zinc  oxide  are  dissolved  in  85  cc.  of  hot  water;  after  complete 
solution"  the  liquid  should  have  a  density  of  1.72.  This  method 
of  analysis  is  well  adapted  for  plushes  and  other  heavy  silk 
fabrics. 

Experiment  170.  Analysis  of  Fabric  Containing  Wool  and 
Silk.  —  A  weighed  portion  of  the  sample  is  steeped  for  2  minutes 
in  concentrated  hydrochloric  acid  at  120°  F.  This  will  dissolve 
the  silk  without  materially  affecting  the  wool.  Wash  the  residue 
of  wool,  dry,  and  reweigh. 

Experiment  171.  Analysis  of  Fabric  Containing  Wool,  Silk, 
and  Cotton.  —  A  weighed  portion  of  the  sample  is  treated  for 
10  minutes  with  a  cold  solution  of  nickel  hydrate  in  ammonia 
(see  above).  This  will  dissolve  any  silk  present.  Wash  well, 
dry,  and  reweigh.  The  loss  in  weight  represents  silk.  The 
residue  is  next  boiled  for  10  minutes  in  a  5  per  cent,  solution  of 
caustic  potash.  This  will  dissolve  any  wool  present.  Wash 
well,  dry,  and  reweigh.  The  loss  in  weight  represents  wool, 
while  the  residue  consists  of  cotton  (see  Exp.  167  for  correction 
to  apply  to  weight  of  cotton). 

Experiment  172.  Distinction  between  True  Silk  and  Artificial 
Silk.  —  Artificial  silk  (or  lustra-cellulose)  is  a  fibre  prepared 


312  DYEING   AND    TEXTILE   CHEMISTRY. 

from  a  solution  of  collodion  or  other  cellulose  solution.  .  It  con- 
sists of  cellulose,  whereas  true  silk  is  a  nitrogenous  animal 
substance.  Artificial  silk  burns  readily  in  the  air  like  cotton, 
without  evolving  a  strong  odor;  while  silk  burns  slowly,  and 
emits  a  characteristic  odor.  To  estimate  the  amount  of  artificial 
silk  present  in  a  mixed  fabric,  a  weighed  portion  of  the  sample  is 
treated  at  the  ordinary  temperature  for  20  minutes  with  an  alka- 
line solution  of  copper  sulphate.  This  will  completely  dissolve 
the  natural  silk,  leaving  the  artificial  fibre  as  a  residue.  The 
latter  is  thoroughly  washed,  dried,  and  reweighed.  The  alkaline 
solution  of  copper  sulphate  is  prepared  by  dissolving  10  grams 
of  copper  sulphate  in  100  cc.  of  water  and  5  cc.  of  glycerin;  a 
strong  solution  of  caustic  soda  is  then  added  until  the  precipitate 
at  first  formed  just  redissolves. 

Experiment  173.  To  Distinguish  between  Cotton  and  Linen.  — 
(a)  Steep  the  sample  containing  these  two  fibres  for  2  minutes  in 
concentrated  sulphuric  acid;  wash  well  with  water,  gently  rub 
with  the  fingers,  and  finally  steep  in  dilute  ammonia;  then  squeeze 
and  dry.  The  cotton  fibres  will  be  converted  into  a  jelly-like 
mass  by  the  action  of  the  acid,  and  is  more  or  less  completely 
removed  by  the  rubbing  and  washing.  The  linen  remains  but 
little  altered.  By  weighing  the  sample  before  and  after  the 
treatment  an  approximate  idea  of  the  amounts  of  cotton  and 
linen  present  may  be  obtained,  (b)  Steep  the  sample  to  be 
tested  in  olive  oil;  then  press  between  filter  paper  to  remove  the 
excess  of  oil.  The  linen  fibres  will  become  gelatinous  in  appear- 
ance and  translucent,  whereas  the  cotton  remains  unaltered. 
When  placed  on  a  dark  background  the  linen  fibres  will  riow 
appear  dark  and  the  cotton  fibres  light,  (c)  Steep  the  sample 
to  be  tested  in  an  alcoholic  solution  of  rosolic  acid,  and  then  in  a 
strong  solution  of  caustic  soda;  finally  rinse  in  water.  The  linen 
fibres  will  become  rose-colored,  while  the  cotton  is  colored  much 
lighter  and  most  of  the  color  is  removed  by  the  rinsing.  None  of 
these  tests  are  very  satisfactory  when  the  linen  has  been  bleached 
for  then  its  cellulose  is  practically  identical  with  that  of  cotton. 
The  most  satisfactory  means  of  qualitatively  distinguishing  linen 


ANALYSIS  OF   TEXTILE  FABRICS.  313 

from  cotton  is  by  a  microscopic  examination,  as  these  fibres 
exhibit  very  different  microscopic  properties  (see  the  author's 
Textile  Fibres). 

Experiment  174.  To  Distinguish  between  True  Silk  and 
Tussah  Silk.  —  Tussah  silk  (and  the  wild  silks  in  general)  may 
be  distinguished  from  true  silk  by  the  following  reactions: 

(a)  Tussah  silk  is  only  partially  dissolved  by  cold  concentrated 
hydrochloric  acid  (sp.  gr.  1.16),  even  on  standing  for  48  hours; 
whereas  true  silk  dissolves  almost  instantly. 

(b)  Tussah  silk  requires  a  comparatively  long  time  to  dissolve 
in  the  solution  of  basic  zinc  chloride,  mentioned  in  Exp.  168; 
whereas  true  silk  dissolves  quite  readily. 

(c)  True  silk  dissolves  completely  in  a  semi- saturated  solu- 
tion of  chromic  acid  when  boiled  for  i  minute;  whereas  tussah 
silk  remains  unaltered  after  boiling  for  2   to  3  minutes  in  this 
solution. 

(d)  To  estimate  the  amount  of  tussah  silk  in  a  fabric,  weigh 
off  a  portion  of  the  sample  and  steep  for  10  minutes  in  cold  con- 
centrated hydrochloric  acid;  wash  the  residue  thoroughly,  dry,  and 
reweigh.     The  loss  in  weight  represents  the  true  silk  while  the 
residue  consists  of  tussah  silk. 


QUIZ  27. 

759.  Describe  the  method  for  determining  the  amounts  of  wool  and  cotton 
in  a  fabric. 

760.  Why  is  a  correction  applied  to  the  quantity  of  cotton,  and  what  does 
this  correction  amount  to  ? 

761.  Give  two  methods  for  determining  the  amounts  of  silk  and  cotton  in  a 
fabric. 

762.  How  is  the  ammoniacal  nickel  hydrate  solution  prepared?    Which 
fibre  is  soluble  in  this  reagent? 

763-   Give  the  method  of  preparing  the  solution  of  basic  zinc  chloride. 
Which  fibre  is  soluble  in  this  reagent  ? 

764.  If  a  fabric  contains  wool  and  silk,  what  method  would  you  employ  to 
determine  the  amount  of  each  ? 

765.  A  fabric  contains  wool,  silk,  and  cotton  fibres;  how  would  you  deter- 
mine the  amount  of  each  fibre  present  ? 


314  DYEING   AND    TEXTILE   CHEMISTRY. 

766.  Of  what  does  artificial  silk  consist?     How  may  this  fibre  be  qualita- 
tively distinguished  from  true  silk? 

767.  Give  a  method  for  determining  the  amount  of  artificial  silk  in  a  fabric. 

768.  Describe   several   methods   for  distinguishing   between   cotton   and 
linen  fibres  in  a  fabric.     Will  bleached  linen  react  in  a  similar  manner  ? 

769.  Give  several  reactions  to  distinguish  between  tussah  silk  and  true 
silk.     What  is  the  difference  in  origin  between  tussah  silk  and  true  silk? 

770.  How  would  you  estimate  the  amounts  of  tussah  silk  and  true  silk  in  a 
fabric  ? 


SECTION   XXVIII. 
ANALYSIS  OF  TEXTILE  FABRICS. 

Experiment  175.  Estimation  of  Sizing  and  Dressing 
Materials  in  a  Fabric.  —  These  materials  include  sizing,  such 
as  starch,  clay,  etc.,  used  for  stiffening  a  warp  or  fabric;  finishing 
materials,  such  as  glue,  magnesium  chloride,  etc.,  which  may 
be  added  to  give  a  certain  finish  to  the  cloth;  mordants  and 
dyestuffs,  as  well  as  grease,  etc.,  which  may  be  present  in  the 
fabric.-  A  weighed  sample  of  the  fabric  is  boiled  for  15  minutes 
in  a  3  per  cent,  solution  of  hydrochloric  acid;  wash  well,  and  boil 
for  10  minutes  in  a  i  per  cent,  solution  of  soda  ash;  wash  well 
again,  and  dry.  Reweigh,  and  the  loss  will  represent  the  amount 
of  size  and  dressing  materials. 

Experiment  176.  Conditioning  of  Textile  Materials.  —  By 
"conditioning"  is  meant  the  estimation  of  the  amount  of  moisture 
present  in  a  yarn  or  fabric  and  the  subsequent  calculation  of 
the  amount  of  normally  dry  fibre  present  in  the  sample.  The 
test  is  usually  carried  out  by  means  of  a  specially  constructed 
conditioning  oven  wherein  the  weighed  sample  is  heated  at  about 
220°  F.  until  the  moisture  is  completely  driven  out.  The  residue 
consists  of  "  bone-dry  "  fibre,  and  the  loss  is  moisture.  To  the 
weight  of  the  dry  residue  is  then  added  the  amount  of  moisture 
corresponding  to  that  normally  present  in  the  fibre  under  examin- 
ation. This  amount  is  termed  the  "regain,"  and  though  the 
standard  varies  in  different  localities,  for  America  it  may  be 
taken  as  follows: 

For  materials  of  wool 18    per  cent. 

For  materials  of  cotton 8£  per  cent. 

For  silk n    per  cent. 

Where  a  special  conditioning  oven  is  not  available  the  moisture 
test  may  be  made  on  a  small  sample  contained  in  a  weighing 

315 


316  DYEING  AND    TEXTILE  CHEMISTRY. 

bottle  by  heating  in  an  ordinary  drying  oven.  The  test  is  much 
more  accurate,  however,  when  a  relatively  large  amount  of 
material  is  used. 

Place  100  grams  of  woolen  yarn  in  the  conditioning  oven  and 
heat  at  220°  F.  until  no  further  loss  in  weight  occurs.  This 
will  usually  require  .3  to  4  hours.  Note  the  loss  in  weight.  For 
example,  suppose  this  loss  to  be  19.6  grams;  then 

Original  weight 100.      grams. 

Loss  as  moisture .< 19.6    grams. 

Residue  as  bone-dry  fibre 80.4    grams. 

Add  regain,  18  per  cent,  of  this 14.47  grams. 

Normal  weight 94.87  grams. 

Hence,  the  sample  contained  94.87  per  cent,  of  "conditioned" 
or  normal  wool. 

Repeat  the  test,  using  samples  of  loose  wool,  worsted  tops,  raw 
cotton,  cotton  yarn,  raw  silk,  etc.,  and  calculate  the  amounts  of 
conditioned  fibre  in  each  case. 

Experiment  177.  Estimation  of  Oil  and  Grease  in  Fabrics.  — 
For  analytical  purposes,  these  substances  are  best  extracted  by 
means  of,  petroleum  ether  (ligroin)  in  a  Soxhlet  extraction 
apparatus.  A  weighed  quantity  (about  i  gram)  of  the  fabric 
to  be  tested  is  placed  in  the  capsule  of  the  extractor;  pour  60  cc. 
of  petroleum  ether  in  the  tared  flask  of  the  apparatus.  Connect 
the  extractor  with  its  condenser  and  heat  on  a  water-bath, 
regulating  the  temperature  so  that  the  solvent  siphons  over  about 
every  5  minutes.  Continue  the  extraction  for  i  hour;  then  dis- 
connect the  extractor,  distil  off  the  solvent,  dry  the  flask  in  a 
water  oven,  cool  and  finally  reweigh.  The  increase  in  weight 
of  the  flask  will  represent  the  amount  of  grease  and  oil  in  the 
fabric. 

Experiment  178.  Detection  of  Mineral  Oil  in  Textile  Fabrics.  — 
This  oil  is  sometimes  employed  for  the  oiling  of  stock,  and  is 
sometimes  difficult  to  remove  by  simple  scouring,  if  such  oil  is  of 
improper  quality.  Extract  about  10  grams  of  the  sample  with 
50  cc.  of  carbon  tetrachloride  in  a  Soxhlet  extractor.  Distil 
off  the  solvent;  mix  the  residue  of  grease  and  oil  with  water.  If 


ANALYSIS  OF   TEXTILE  FABRICS. 

mineral  oil  is  present  a  fluorescence  will  be  noticed  on  the  surface 
of  the  water. 

Experiment  179.  Detection  of  Rosin  Oil  in  Textile  Fabrics.  — 
A  weighed  portion  (about  5  grams)  of  the  sample  is  extracted 
with  50  cc.  of  ligroin  (as  in  Exp.  176).  To  the  residue  of 
grease,  after  evaporation  of  the  solvent,  add  5  cc.  of  acetic  anhy- 
dride; shake  well  at  a  gentle  heat,  then  allow  to  cool,  draw  off 
the  layer  of  acetic  anhydride  with  a  pipette,  and  add  to  it  a  drop 
of  concentrated  sulphuric  acid.  The  production  of  a  violet  color 
(which,  however,  is  not  permanent)  will  indicate  the  presence  of 
resin  oils.  If  the  presence  of  resin  (colophony)  in  a  textile 
fabric  is  suspected,  the  former  may  be  first  converted  into  resin 
oils  by  boiling  with  dilute  hydrochloric  acid;  after  which  the  test 
is  to  be  carried  out  as  given. 

Experiment  180.  Estimation  of  Mineral  Matter  in  a  Fabric.  — 
A  weighed  portion  (i  to  2  grams)  of  the  sample  is  clipped  up 
and  ignited  in  a  tared  porcelain  crucible  to  a  complete  ash/  The 
weight  of  the  latter  represents  the  amount  of  mineral  matter  in 
the  sample. 

Experiment  181.  Determination  of  the  Nature  of  Sizing  on  a 
Fabric.  —  The  principal  ingredients  liable  to  be  present  in  the 
sizing  on  a  fabric  are  starch,  dextrin,  gums,  gelatin,  Irish  moss, 
sugar,  resin,  fatty  matters,  and  various  inorganic  substances  such 
as  china  clay,  gypsum,  talc,  magnesia,  magnesium  chloride,  cal- 
cium chloride,  zinc  chloride,  alumina,  etc. 

To  test  for  these  substances  take  a  sample  of  the  fabric  meas- 
uring about  30  to  40  square  inches,  and  boil  for  several  hours  in 
about  250  cc.  of  water.  This  will  dissolve  all  soluble  materials, 
including  starch,  dextrin,  gums,  gelatin,  Irish  moss,  sugar,  and 
the  chlorides  of  magnesium,  calcium,  and  zinc.  Test  this 
aqueous  extract  in  the  following  manner: 

(1)  Starch.  —  Add  to  a  portion  of  the  solution  a  few  drops  of 
iodine  solution   (in  potassium  iodide) ;  the  formation  of  a  blue 
color  indicates  the  presence  of  starch. 

(2)  Dextrin  and  gums.  —  If  no  starch  is  present,  concentrate 
a  portion  of  the  extract  by  boiling;  cool,  and  add  three  times  its 


3l8  DYEING  AND    TEXTILE  CHEMISTRY. 

volume  of  alcohol.     Dextrin  or  gums,  if  present,  will  be  precipi- 
tated.    These  may  be  filtered  off  and  identified  by  burning. 

(3)  Gelatin.  —  To  a  portion  of  the  extract  add  some  tannic 
acid  solution,  which  will  give  a  precipitate  in  the  presence  of 
gelatin. 

(4)  Sugar  and  glucose.  —  These  may  be  detected  by  boiling  a 
portion  of  the  extract  with  a  little  dilute  hydrochloric  acid,  and 
adding  a  few  drops  of  Fehling's  solution,  when  a  red  precipitate 
of  cuprous  oxide  will  be  formed  in  the  presence  of  a  sugar. 

(5)  Irish  moss  (or  other  lichen  jelly)  may  be  considered  to  be 
present  if  an  organic  substance  is  known  to  exist  in  the  extract, 
and  yet  no  evidence  of  the  foregoing  compounds  is  found. 

(6)  Chlorides  may  be  detected  by  adding  a  few  drops  of  nitric 
acid  to  the  extract,  followed  by  a  few  drops  of  a  solution  of  silver 
nitrate;  the  formation  of  a  white  precipitate  of  silver  chloride 
will  show  the  presence  of  chlorides. 

(7)  Zinc  may  be  detected  by  adding  ammonium  sulphide  to 
the  extract;  a  white  precipitate  of  zinc  sulphide  will  indicate  the 
presence  of  this  metal. 

(8)  Calcium  may  be  detected  by  adding  ammonium  oxalate 
solution  to  a  portion  of  the  extract,  when  a  white  precipitate  of  cal- 
cium oxalate  will  be  formed  in  the  presence  of  calcium  compounds. 

(9)  Magnesium  may  be  detected  by  adding  a  few  drops  of 
ammonia  water  and  ammonium  chloride  solution  to  a  portion  of 
the  extract,  followed  by  the  addition  of  sodium  phosphate  solution. 
The  formation  of  a  white,  crystalline  precipitate  of  magnesium 
ammonium  phosphate  will  indicate  the  presence  of  magnesium 
salts. 

(10)  Sulphates,  which  may  at  times  be  present  as  magnesium 
sulphate  (Epsom's  salts),  may  be  detected  by  adding  a  few  drops 
of  hydrochloric  acid  to  a  portion  of  the  extract,  followed  by  the 
addition  of  a  few  drops  of  a  solution  of  barium  chloride.     The 
formation  of  a  white  precipitate  of  barium  sulphate  will  indicate 
the  presence  of  sulphates. 

(n)  Resins,  fats,  and  oils  may  be  tested  for  by  the  methods 
already  given  in  the  preceding  experiments. 


ANALYSIS  OF   TEXTILE  FABRICS.  319 

(12)  China  clay  (aluminium  silicate),  gypsum  (calcium  sul- 
phate), and  talc  (magnesium  silicate)  are  insoluble,  even  in 
strong  acids,  and  may  be  found  in  the  ash  left  from  the  ignition 
of  a  portion  of  the  fabric,  after  first  boiling  in  water  to  remove  all 
soluble  matters.  It  will  hardly  be  necessary  here  to  discriminate 
between  these  three  substances  themselves,  as  such  an  analysis 
would  be  both  tedious  and  complicated. 

Experiment  182.  Determination  of  the  Nature  of  Mordants  on 
Woolen  Fabrics.  —  To  determine  the  character  of  the  mordant 
which  may  be  present  in  a  yarn  or  fabric,  a  qualitative  analysis  of 
the  ash  must  be  made.  For  this  purpose,  take  about  10  grams 
of  the  clippings  of  the  sample  and  ignite,  in  small  portions  at  a 
time,  thoroughly  in  a  porcelain  crucible  until  all  the  carbon 
and  volatile  matters  have  been  burned  away.  The  different 
mordants  are  then  tested  for  in  the  following  manner: 

(1)  Aluminium  compounds.  —  The  ash  should  be  white,  or 
grayish.     Dissolve  a  portion  in  warm  hydrochloric  acid,   and 
neutralize  the  solution  with  a  slight  excess  of  ammonia.     A  white 
precipitate  of  aluminium  hydrate  will  indicate  the  presence  of 
aluminium.     This  should  be  confirmed  by  heating  a  portion  of 
the   ash   on  charcoal,  moistening  with  a  drop  of  cobalt  nitrate 
solution;  a  blue  color  will  be  obtained  if  aluminium  is  present. 

(2)  Tin   compounds.  —  The    ash   is    also    white   or   grayish. 
Dissolve  in    boiling  hydrochloric   acid,  and    test   a  portion   of 
the  solution   with  sulphuretted  hydrogen  gas.     The  formation 
of   a   brownish   yellow   precipitate   will   indicate    the   presence 
of  tin. 

(3)  Iron  compounds.  —  The  ash  is  reddish  brown  in  color. 
Dissolve  in  warm  hydrochloric  acid.     To  a  portion  of  the  solution 
add  a  drop  of  nitric  acid  and  a  few  drops  of  a  solution  of  potas- 
sium ferrocyanide  (yellow  prussiate).     The  formation  of  a  blue 
precipitate  will  indicate  the  presence  of  iron.     This  may  be  further 
confirmed  by  taking  another  portion  of  the  solution,  adding  a 
drop  of  nitric  acid,  and  a  few  drops  of  a  solution  of  potassium 
sulphocyanide.     The  formation  of  a  red  color  indicates  the  pres- 
ence of  iron. 


320  DYEING   AND    TEXTILE   CHEMISTRY. 

(4)  Chromium  compounds.  —  The  ash  is  yellowish  or  brownish 
green.     Add    a  few   crystals   of   potassium   chlorate    and   fuse. 
The  resulting  yellowish  mass  is  dissolved  in  water;  a  few  drops 
of  acetic  acid  are  added,  and  also  a  solution  of  lead  acetate. 
A  yellow  precipitate  of  lead  chromate  will  indicate  the  presence 
of  chromium. 

(5)  Copper  compounds.  —  The  ash  may  be  brownish  or  black. 
Dissolve  in  warm  hydrochloric  acid,  neutralize  with  an  excess 
of  ammonia  water,  when  the  formation  of  a  blue  color  will 
indicate  the  presence  of  copper. 

In  some  cases,  several  of  these  metals  may  occur  together 
in  the  ash  of  the  fabric.  In  order  to  conduct  a  systematic  test 
for  all  of  them  proceed  in  the  following  manner: 

Boil  up  the  ash  with  a  little  concentrated  hydrochloric  acid, 
and  filter  from  any  insoluble  residue.  To  the  diluted  filtrate  add 
hydrogen  sulphide  until  no  further  precipitation  occurs.  A 
precipitate  will  indicate  the  presence  of  copper  or  tin  (consisting 
of  black  copper  sulphide  or  brown  tin  sulphide).  Filter,  wash  the 
precipitate,  and  treat  with  warm  ammonium  sulphide  solution. 
This  will  dissolve  any  tin  sulphide  and  leave  the  copper  sulphide 
as  a  residue.  Filter  the  latter,  if  present;  dissolve  the  residue 
in  a  small  quantity  of  strong  nitric  acid;  dilute  with  water  and 
add  slight  excess  of  ammonia,  when  the  formation  of  a  blue 
color  will  indicate  the  presence  of  copper.  Tin,  if  present  in  the 
last  filtrate,  may  be  identified  by  adding  slight  excess  of  hydro- 
chloric acid  and  boiling  till  all  odor  of  hydrogen  sulphide  is  gone. 
The  solution  would  now  contain  stannous  chloride;  filter,  and 
pour  into  a  hot  solution  of  mercuric  chloride;  a  white  precipitate 
of  mercurous  chloride  will  indicate  the  presence  of  tin.  The 
filtrate  from  the  precipitated  sulphides  of  copper  and  tin  is  boiled 
until  all  odor  of  hydrogen  sulphide  is  removed.  Add  a  few 
drops  of  concentrated  nitric  acid  and  boil  for  a  few  minutes  longer. 
Add  a  slight  excess  of  ammonia  water  and  boil  again;  this  will 
cause  the  precipitation  of  any  iron,  chromium,  or  aluminium  as 
hydrates.  Filter,  and  wash  the  residue.  Then  boil  up  with  a 
solution  of  potassium  hydrate  which  will  dissolve  out  any  alu- 


ANALYSIS  OF   TEXTILE  FABRICS.  $21 

minium  hydrate.  Filter  from  the  residue  of  iron  and  chromium 
hydrates;  acidify  the  nitrate  with  hydrochloric  acid,  and  then  add 
ammonia  in  slight  excess.  The  formation  of  a  colorless,  gelati- 
nous precipitate  of  aluminium  hydrate  will  indicate  the  presence  of 
aluminium.  The  above  residue  of  iron  and  chromium  hydrates 
is  now  fused  on  a  piece  of  platinum  foil  with  a  small  quantity 
of  sodium  peroxide.  This  will  result  in  the  formation  of  sodium 
chromate,  and  the  fused  mass  will  be  yellow  if  chromium  is 
present.  Dissolve  the  fusion  in  water;  filter  off  any  residue 
of  iron  oxide,  acidify  the  filtrate  with  acetic  acid,  and  add  a 
few  drops  of  lead  acetate  solution.  The  formation  of  a 
yellow  precipitate  of  lead  chromate  will  indicate  the  presence 
of  chromium.  The  residue  of  iron  oxide,  if  present,  is  dis- 
solved in  a  little  hot  concentrated  hydrochloric  acid;  dilute 
with  water  and  add  a  few  drops  of  potassium  ferrocyanide 
solution.  The  formation  of  a  blue  precipitate  indicates  the 
presence  of  iron. 

Analyze  samples  of  cloth  containing  mordants  of 

(a)  iron  and  aluminium. 

(b)  iron  and  chromium. 

(c)  tin  and  aluminium. 

(d)  copper  and  iron. 

(e)  iron,  aluminium,  and  copper. 
(/)  tin,  aluminium,  and  chromium. 

Experiment  183.  Determination  of  the  Nature  of  Mordants 
on  Cotton  Fabrics.  —  The  mordants  which  are  liable  to  be 
present  in  cotton  fabrics  fall  under  three  classes : 

(a)  Those  for  basic  dyes,  including  tannin,  antimony,  iron, 
and  copper. 

(b)  Those    for  alizarin   dyes,  including    tannin,  aluminium, 
iron,  chromium,  and  fatty  acids. 

(c)  Those  for  acid  dyes,  including  tannin,  aluminium,  fatty 
acids,  tin,  and  lead. 

The  first  class  is  the  principal  one,  whereas  the  last  two 
classes  rarely  come  into  observation,  and  then  only  for  a  few 


322  DYEING   AND    TEXTILE   CHEMISTRY.  ' 

specific    colors.     The    various    mordants    may  be    detected    as 
follows : 

(1)  Tannin.  —  A  sample  of   the  fabric  is  boiled  in  a  dilute 
solution  of  soda  ash  for  20  minutes;  the  solution  is  then  poured 
off   and    almost   neutralized   with   hydrochloric    acid.      A   few 
drops  of  ferric  chloride  solution  are  next  added,  when  the  forma- 
tion of  a  black  color  (due  to  tannate  of  iron)  will  indicate  the 
presence  of  tannin. 

(2)  Antimony.  —  A   sample   of  the   fabric   is   boiled   for    15 
minutes  with    concentrated    hydrochloric  acid.      The   solution 
is  faltered  and  diluted  with  water.     A  portion  of  the  filtrate  is 
then  treated  with  hydrogen  sulphide,  when  the  formation  of  a 
yellow  (or  orange)   precipitate   (of  antimony  sulphide)  will  in- 
dicate the  presence  of  antimony.     To  confirm  this,  however,  the 
antimony  sulphide  is  filtered  off  and  dissolved  in  a  little  hot 
concentrated   hydrochloric   acid.     Dilute  with  water,   and   add 
to  the  solution  a  piece  of  zinc  on  platinum  foil.     If  a  black  stain 
forms  on  the  platinum,  the  presence  of  antimony  is  confirmed. 

(3)  Iron.  —  A  portion  of  the  hydrochloric  acid  extract  obtained 
above  is  tested  with  a  few  drops  of  potassium  ferrocyanide  solu- 
tion.    The  formation  of  a  blue  color  will  indicate  the  presence 
of  iron. 

(4)  Copper.  —  Another  portion  of  the  same  acid  solution  as 
above  is  neutralized  with  an  excess  of  ammonia  water.     The 
formation  of  a  blue  color  in  the  liquid  will  indicate  the  presence 
of  copper. 

In  case  the  fabric  is  suspected  to  have  been  dyed  with  alizarin 
colors  (Turkey-red,  etc.),  tannin  may  be  tested  for  in  the  manner 
given  above.  Aluminium,  iron,  chromium,  and  tin  mordants 
may  be  looked  for  according  to  the  methods  given  in  Exp. 
181.  Fatty  acids  may  be  tested  for  by  first  boiling  the  sample 
with  dilute  hydrochloric  acid  (to  decompose  the  fatty  acid  com- 
pounds of  the  metallic  mordants)  and  ithen  extracting  with 
petroleum  ether  and  testing  as  in  Exp.  176. 

When  it  is  suspected  that  the  sample  is  dyed  with  acid  colors 
(which  may  usually  be  told  by  the  color  not  being  at  all  fast  to 


ANALYSIS  OF   TEXTILE  FABRICS.  $2$ 

soap  and  water),  and  it  is  desired  to  identify  the  mordants  used, 
those  of  aluminium,  tannin,  fatty  acid,  and  tin  may  be  detected 
as  given  above. 

(5)  Lead.  —  The  sample  is  boiled  for  20  minutes  in  concen- 
trated nitric  acid.  Dilute  the  solution,  and  filter.  To  a  portion 
of  the  nitrate  add  a  few  drops  of  a  solution  of  potassium  chromate, 
when  the  formation  of  a  yellow  precipitate  of  lead  chromate  will 
indicate  the  presence  of  lead. 

QUIZ  28. 

771.  What  is  meant  by  the  sizing  and  dressing  materials  on  a  fabric? 
How  may  the  amount  of  these  be  estimated  ? 

772.  What  is  meant  by  "conditioning"  ?    What  is  the  meaning  of  "normal" 
fibre  and  "bone-dry"  fibre? 

773.  How  is  the  conditioning  test  usually  made?    What  is  understood  by 
the  "regain"  ?    What  is  the  customary  regain  allowed  for  woolen,  cotton,  and 
silk  fabrics? 

774.  If  100  grams  of  woolen  yarn  give  84  grams  of  bone-dry  fibre,  how 
much  normal  fibre  does  it  contain  ? 

775.  A  shipment  of  12,750  pounds  of  worsted  tops  is  billed  on  a  basis  of 
1 8  per  cent,  regain;  what  would  be  the  conditioned  weight  allowed  if  a  test 
showed  the  presence  of  16  per  cent,  of  moisture? 

776.  A  firm  buys  1125  pounds  of  raw  silk  at  $4.72  per  pound  with  n  per 
cent,  regain.     The  conditioning  test  gives  12 J  per  cent,  of  moisture;  what  was 
the  amount  of  the  bill  ? 

777.  A  cotton  mill  manufactures  125,000  pounds  of  cotton  yarn  per  month 
at  an  average  selling  price  of  38  cents  per  pound.     This  yarn  when  sold  aver- 
ages 4.2  per  cent,  moisture.     At  the  end  of  the  year  the  mill  shows  a  loss  of 
$12,500.   The  mill  then  dampens  its  yarn  so  that  it  contains  8  per  cent,  moisture. 
What  profit  should  the  mill  show  at  the  end  of  the  second  year? 

778.  How  is  the  amount  of  oil  and  grease  in  a  fabric  determined  ?    Describe 
the  operation  of  extraction  in  a  Soxhlet  apparatus. 

779.  How  is  the  presence  of  a  mineral  oil  in  a  fabric  detected? 

780.  What  is  a  resin  oil  ?    How  is  the  presence  of  such  detected  in  fabrics  ? 
How  is  the  presence  of  resin  itself  shown  ? 

781.  How  would  you  estimate  the  total  amount  of  mineral  matter  present 
in  a  textile  fabric? 

782 .  What  are  the  chief  mordants  liable  to  occur  in  woolen  goods  ?    What 
mordants  yield  a  white  ash  on  ignition  ? 

783.  Give  the  method  for  testing  for  aluminium  compounds  on  a  woolen 
fabric.     For  chromium.     For  tin. 


324  DYEING  AND    TEXTILE   CHEMISTRY. 

784.  Suppose  a  sample  of  woolen  cloth  contained  iron  and  aluminium 
mordants;  how  would  you  show  their  presence? 

785.  If  iron,  aluminium,  and  copper  compounds  were  present  in  a  woolen 
fabric,  how  would  you  conduct  the  analysis  ? 

786.  Name  the  principal  ingredients  which  may  be  present  in  the  sizing  of 
a  textile  fabric. 

787.  Which  of  the  common  sizing  ingredients  are  soluble  in  water  and 
which  are  not  ? 

788.  Give  methods  for  the  detection  of  the  following  substances  in  the 
sizing  of  fabrics: 

Starch  Gelatin  Zinc  chloride 

Dextrin  Sugar  Epsom's  salts 

China  clay  Calcium  chloride 

789.  What  are  the  chief  mordants  likely  to  be  present  in  cotton  fabrics? 

790.  How  would  you  show  the  presence  of  tannin  mordant  on  a  cotton 
fabric?     Of  antimony?     Of  iron?     Of  fatty  acids ? 

791.  How  would  you  show  the  presence  of  lead  compounds  in  a  cotton 
fabric? 


APPENDIX 

USEFUL  DATA    FOR  DYERS   AND   TEXTILE  CHEMISTS 

i .  Hydrometers.  —  The  strength  of  many  solutions  is  most 
conveniently  measured  by  a  determination  of  the  density.  The 
instrument  used  for  this  purpose  is  known  as  a  hydrometer. 

The  Twaddle  Hydrometer.  —  This  is  an  instrument  for 
measuring  the  density  of  solutions  and  liquids.  Each  Twaddle 
degree  (abbreviated  to  Tw.)  represents  0.005  units  of  specific 
gravity,  and  the  starting  point  for  liquids  heavier  than  water  is 
the  density  of  water,  which  is  i  sp.  gr.  and  is  made  equal  to 
o  degrees  Tw.  Hence  i°  Tw.  would  be  1.005  SP-  gr-J  2°  Tw. 
would  be  i.oio  sp.  gr.;  10°  Tw.  would  be  1.050  sp.  gr.,  etc.  To 
convert  specific  gravity  readings  into  degrees  Twaddle,  and  vice 
versa,  the  following  formulas  may  be  employed: 

Twaddle  degrees  =  (specific  gravity  —  i)  X  200; 
specific  gravity  —  i 

0.005 
Specific  gravity  =  (Tw.°  X  0.005)  +  *• 

The  Beaume  Hydrometer.  —  This  is  an  instrument  very  similar 
to  that  of  Twaddle,  but  its  method  of  graduation  is  different. 
The  degrees  Beaume  (abbreviated  to  Be.)  bear  no  direct  relation 
to  actual  specific  gravity,  but  this  hydrometer  is  largely  used  for 
technical  work  both  in  Europe  and  America.^  The  graduation 
for  liquids  heavier  than  water  is  made  in  the  following  manner. 
The  zero  mark  (as  with  the  Twaddle  instrument)  is  obtained  by 
immersion  in  distilled  water;  the  instrument  is  then  placed  in  a 
solution  containing  15  parts  by  weight  of  common-salt  and  85 
parts  by  weight  of  water,  and  the  point  to  which  the  hydrometer 
sinks  is  called  15.  The  interval  between  this  point  and  the  zero 
is  then  divided  into  15  equal  parts,  and  the  graduation  continued 
as  far  as  desirable.  The  degrees  Beaume  represent  greater 

325 


326 


DYEING  AND    TEXTILE  CHEMISTRY. 


COMPARISON  BETWEEN  THE  SPECIFIC  GRAVITY  OF  BEAUME   AND  TWADDLE 


Tw. 

B. 

Sp.  gr. 

Tw. 

B. 

Sp.  gr. 

Tw. 

B. 

Sp.  gr. 

0 

0 

.000 

58 

32-4 

.  290 

116 

53-o 

.580 

i 

0.7 

.005 

59 

32.8 

•295 

117 

53-3 

.585 

2 

1.4 

.010 

60 

33-3 

.300 

118 

53-6 

•590 

3 

2.  I 

.015 

6! 

33-7 

•  3°5 

119 

53-9 

•595 

4 

2-7 

.020 

62 

34-2 

.310 

120 

54-i 

.600 

5 

3-4 

.025 

63 

34-6 

•3i5 

121 

54-4 

.605 

6 

4-1 

.030 

64 

35-o 

.320 

122 

54-7 

.  610 

7 

4-7 

•035 

65 

35-4 

•325 

I23 

55-° 

.615 

8 

5-4 

.040 

66 

35-8 

•330 

124 

55-2 

.  620 

9 

6.0 

.045 

67 

36.2 

•335 

125 

55-5 

.625 

10 

6.7 

.050 

68 

36.6 

•  340 

126 

55-8 

•  630 

n 

7-4 

•°55 

69 

37-o 

•345 

127 

56.  o 

•635 

12 

8.0 

.060 

70 

37-4 

•35° 

128 

56.3 

.  640 

13 

8-7 

.065 

37-8 

•355 

129 

56.6 

•645 

14 

9-4 

.070 

72 

38.2 

•  360 

I30 

56-9 

•  650 

15 

IO.O 

•°75 

73 

38.6 

•365 

57-i 

•655 

16 

10.  6 

.080 

74 

39.0 

•370 

I32 

57-4 

.660 

3' 

II.  2 

11.9 

.085 
.090 

39-4 
39-8 

•375 
.380 

133 

57-7 
57-9 

.665 
.  670 

19 

12.4 

•°95 

77 

40.  i 

•385 

135 

58.2 

•675 

20 

13.0 

.100 

78 

40.5 

•39° 

136 

58-4 

.680 

21 

13.6 

•105 

79 

40.8 

•395 

137 

58.7 

.685 

22 

14.2 

.  no 

80 

41.2 

.400 

138 

58.9 

.  690 

23 

14.9 

•US 

81 

41.  6 

•405 

139 

59-2 

•695 

24 

15-4 

.  120 

82 

42.0 

.410 

140 

59-5 

.700 

25 

16.  o 

•125 

83 

42.3 

•  415 

141 

59-7 

•705 

26 

16.5 

.130 

84 

42.7 

.420 

142 

60.0 

.710 

27 

17.1 

•135 

85 

.425 

143 

60.2 

•  7Z5 

28 

17.7 

.  140 

86 

43-4 

•43° 

144 

60.4 

.720 

29 

18.3 

•145 

87 

43-8 

•435 

US 

60.6 

•725 

30 

18.8 

.150 

88 

44.1 

.440 

146 

60.  9 

•730 

31 

19-3 

•155 

89 

44-4 

•445 

147 

61.1 

•735 

32 

19.8 

.160 

90 

44-8 

•45° 

I48 

61.4 

.740 

33 

20.3 

.165 

45-i 

•455 

149 

61.6 

•745 

34 

20.9 

.170 

92 

45-4 

.460 

15° 

61.8 

•750 

35 

21.4 

93 

45-8 

•465 

62.1 

•755 

36 

22.  O 

!i8o 

94 

46.1 

•47° 

152 

62.3 

.760 

22.5 

.185 

95 

46.4 

•475 

153 

62.5 

•765 

38 

23.0 

.190 

96 

46.7 

.480 

154 

62.8 

•77° 

39 

23-5 

•195 

97 

47-1 

•485 

155 

63.0 

•775 

40 

24.O 

.200 

98 

47-4 

.490 

156 

63.2 

.780 

24.5 

.205 

99 

47-8 

•495 

157 

63-5 

•785 

42 

25.0 

.  2IO 

IOO 

48.1 

.500 

158 

63-7 

.790 

43 

25-5 

.215 

101 

48.4 

•5°5 

159 

64.0 

•795 

44 

26.0 

.  22O 

102 

48.7 

.510 

160 

64.2 

.800 

45 

26.4 

.225 

103 

49.0 

161 

64.4 

.805 

46 

26.9 

.230 

IO4 

49-4 

.520 

162 

64.6 

.810 

47 

27.4 

•235 

IO5 

49-7 

•525 

163 

64.8 

•815 

48 

27.9 

.  240 

1  06 

50.0 

•53° 

164 

65.0 

.820 

49 

28.4 

•245 

107 

5°-3 

•535 

165 

65.2 

.825 

5° 

28.8 

.250 

108 

50.  6 

•  540 

1  66 

65.5 

.830 

29-3 

•255 

109 

5°-9 

•545 

167 

65.7 

•835 

52 

29-7 

.260 

no 

Si-2 

•55° 

1  68 

65.9 

.840 

53 

30.2 

.265 

in 

51-5 

•555 

169 

66.1 

•  845 

54 

30.6 

.270 

112 

51-8 

.560 

170 

66.3 

•  850 

55 

3*.  i 

.275 

113 

52.1 

•565 

171 

66.5 

•855 

56 

31-5 

.280 

114 

52-4 

•570 

172 

66.7 

.860 

57 

32.0 

1.285 

H5 

52-7 

•575 

173 

67  .0 

i  .  865 

APPENDIX.  327 

density  than  corresponding  degrees  Twaddle.  The  table  on  the 
previous  page  shows  the  equivalence  between  specific  gravity, 
degrees  Twaddle,  and  degrees  Beaume. 

A  solution  of  a  certain  density  may  be  diluted  with  water 
(density  i.ooo)  to  a  solution  of  another  specified  density  in  accord- 
ance with  the  following  formula: 
Let  V  =  volume  of  strong  solution, 
v  =  volume  of  water  to  be  added, 
D=  density  of  strong  solution  (in  specific  gravity), 
d  —  density  of  diluted  solution  (in  specific  gravity) . 

D-  d 


Then  v  =  V  X 


d  -  i 


If  the  densities  are  expressed  in  degrees  Twaddle,  the  formula 
becomes  :  , 


, 

I 

where  T  =  density  of  strong  solution  in  degrees  Twaddle. 
t  —  density  of  diluted  solution  in  degrees  Twaddle. 

EXAMPLE.  —  How  much  water  would  it  be  necessary  to  add 
to  100  cc.  of  a  solution  of  sulphuric  acid  of  1.84  sp.  gr.  to  give  a 
solution  of  1.  1  2  sp.  gr.  ? 

.   1.84  —   1.  12 

V   =    100  X  --  -  -   =  600  CC. 
1.  12   —    I 

How  much  water  must  be  added  to  i  litre  of  a  solution  of  caustic 
soda  of  90°  Tw.  to  reduce  it  to  35°  Tw.  ? 

v  =  i  x  9°  ~  35  =  1.571  litres 
o  ^ 

=  I571  cc. 

2.  Equivalents  of  Common  Use  in  Measuring.  —  In  all  scientific 
and  accurate  work  the  metric  system  of  weights  and  measures  is 
universally  employed.  It  is  presumed  that  the  student  is  familiar 
in  a  general  way  with  the  method  and  values  of  the  metric  system, 
but  his  attention  is  called  at  this  point  to  following  equivalents, 
both  of  the  metric  system  and  the  common  English  system,  which 
will  be  found  useful  and  practical  for  reference. 


328 


DYEING   AND    TEXTILE   CHEMISTRY. 


litre  (/.)  =  1000  cubic  centimetres  (cc.). 

litre  of  water  weighs  i  kilogram  (kilo.). 

cc.  of  water  weighs  i  gram  (gm.). 

cubic  foot  of  water  weighs  62.5  pounds. 

gram  =  1000  milligrams  (mgm.). 
i  kilogram  =  1000  grams  =2.2  pounds, 
i  pound  (Avoir.)  =  453.9  grams, 
i  gallon  (U.  S.)  =  231  cubic  inches, 
i  gallon  water  =8.3  pounds, 
i  pint  water  =  i  pound  (approximately), 
i  litre  =  i  quart  (approximately). 

To  convert  feet  to  metres  multiply  by  0.3. 
Metres  to  feet  multiply  by  3.3. 
Cubic  feet  to  gallons  multiply  by  7.5. 
Gallons  to  cubic  feet  multiply  by  0.13. 
Cubic  feet  to  litres  multiply  by  28.33. 
Litres  to  cubic  feet  multiply  by  0.035. 
Inches  to  centimeters  multiply  by  2.5. 
Centimeters  to  inches  multiply  by  0.4. 
Ounces  to  grams  multiply  by  28.35. 
Grams  to  ounces  multiply  by  0.04. 
Grains  to  grams  multiply  by  0.065. 
Grams  to  grains  multiply  by  15.43. 
Yards  to  metres  multiply  by  0.9. 
Metres  to  yards  multiply  by  i.i. 
Quarts  to  litres  multiply  by  0.95. 
Litres  to  quarts  multiply  by  1.06. 
Gallons  to  litres  multiply  by  3.78. 
Litres  to  gallons  multiply  by  0.26. 

An  English  (Imperial)  gallon  is  larger  than  the  United  States  gallon;  it 
contains  277!  cubic  inches  =  4.54  litres;  it  contains  10  pounds  of  water. 


CONVERSION    OF    KILOGRAMS    INTO    POUNDS. 


Kilos. 

Lbs. 

Kilos. 

Lbs. 

Kilos. 

Lbs. 

Kilos. 

Lbs. 

i 

2i 

.  7 

?Si 

40 

88 

IOO 

220^ 

2 

4$ 

8 

17! 

50 

IIO^ 

200 

441 

3 

6f 

9 

19^ 

60 

132 

300 

661  J 

4 

g| 

10 

22i 

70 

154 

400 

882 

5 

ii 

20 

441 

80 

176 

500 

1102^ 

6 

13* 

30 

66| 

90 

198 

600 

1323 

APPENDIX. 
CONVERSION    OF    POUNDS    INTO    KILOGRAMS. 


329 


Lbs. 

Kilos. 

Lbs. 

Kilos. 

Lbs. 

Kilos. 

Lbs. 

Kilos. 

I 

0-453 

II 

4.984 

21 

9-5I5 

40 

18.125 

2 

0.906 

12 

5-437 

22 

9.968 

50 

22.  656 

3 

1-359 

!3 

5.890 

23 

10.  421 

60 

27.187 

4 

i.  812 

14 

6-343 

24 

10.874 

70 

3I-7I9 

5 

2.  265 

15 

6.796 

25 

11.327 

80 

36.  250 

6 

2.719 

16 

7.249 

26 

11.780 

90 

40.  781 

8 

3.172 
3.625 

i? 

18 

7.702 
o'l5§ 

27 
28 

12.686 

IOO 

200 

45-392 
90.  625 

9 

4.078 

19 

8.608 

29 

I3-I39 

300 

135-937 

10 

4.531 

20 

9.062 

3° 

13-594 

4OO 

181.  250 

CONVERSION    OF    OUNCES    INTO    GRAMS. 


Ozs. 

Grams. 

Ozs. 

Grams. 

Ozs. 

Grams. 

Ozs. 

Grams. 

I 

28-35 

5 

141.75 

9 

255-I5 

13 

368.54 

2 

56.70 

6 

170.10 

10 

283.50 

14 

396.89 

3 

85-05 

7 

198.45 

ii 

311.84 

15 

425.24 

4 

113.40 

8 

226.80 

12 

340.  19 

16 

453-59 

CONVERSION    OF    GRAMS    INTO    OUNCES    AND    GRAINS. 


Grams. 

Ozs. 

Grains. 

Grams. 

Ozs. 

Grains. 

Grams. 

Ozs. 

Grains. 

I 

IC.  47 

22 

7CC 

44 

241 

2 

2O.  O 

24 

37O 

AC 

2C  7 

3 

4 

0~-V 

46.3 
61.7 

77  2 

25 
26 

27 



386 
401 

4-1  7 

46 

47 
48 

272 
288 

2O2 

6 

//•  j 

92.  6 

Is 

47,2 

40 

6^0 
2,10 

7 

1  08 

20 

I 

IO 

C.Q 

224 

I 

123 

^O 

2C 

CT 

2  ^O 

9 

10 

ii 

12 
13 
14 

T  C. 

139 
154 
170 

185 
2OI 

216 

221 

31 
32 

33 
34 
35 
36 

•37 

41 
56 
72 

87 
IO2 

118 

177 

52 

53 
54 
55 
56 
57 
n8 

2 
2 

365 
380 

395 
4H 
427 

5 
20 

16 

247 

3* 

1  40 

rn 

2 

26 

i7 
18 



262 

278 

39 
40 

l64 
1  80 

60 

7O 

2 
2 

5i 

2O£ 

10 

203 

41 

lot; 

80 

2 

260 

20 

3OO 

42 

2IO 

QO 

7 

76 

21 

3,24 

47 

226 

IOO 

7 

2  2O 

22 

34O 

330 


DYEING   AND    TEXTILE   CHEMISTRY. 


3.     Thermometry.     Comparison   of  Centigrade  Thermometer 
with  Fahrenheit. 


Deg. 

Cent. 

Deg. 

Fahr. 

Deg. 
Cent. 

Deg. 

Fahr. 

Deg. 
Cent. 

Deg. 

Fahr. 

Deg. 

Cent. 

Deg. 

Fahr. 

no 

230 

80 

I76. 

50 

122. 

20 

68. 

109 

228.2 

79 

174.2 

49 

I2O.  2 

19 

66.2 

108 

226.4 

78 

172.4 

48 

Il8.4 

18 

64.4 

107 

224.  6 

77 

170.  6 

47 

116.6 

17 

62.6 

106 

222.8 

76 

168.8 

46 

II4.8 

16 

60.8 

io5 

221. 

75 

167. 

45 

H3- 

15 

59- 

104 

219.2 

74 

165.2 

44 

III.  2 

14 

57-2 

103 

217.4 

73 

163.4 

43 

109.4 

13 

55-4 

IO2 

215.6 

72 

161.6 

42 

107.  6 

12 

53-6 

IOI 

213.8 

7i 

159.8 

4i 

105.8 

II 

51-8 

IOO 

212. 

70 

158. 

40 

104. 

IO 

5°- 

99 

2IO.  2 

69 

156.  2 

39 

102.  2 

9 

48.2 

98 

208.  4 

68 

154.4 

38 

IOO.4 

8 

46.4 

97 

206.6 

67 

152.6 

37 

98.6 

7 

44.6 

96 

204.8 

66 

150.8 

36 

96.8 

6 

42.8 

95 

203. 

65 

149- 

35 

95- 

5 

41. 

94 

201.  2 

64 

147.2 

34 

93-2 

4 

39-2 

93 

199.4 

63 

145-4 

33 

91.4 

3 

37-4 

92 

197.6 

62 

143  -6 

32 

89.6 

2 

35-6 

9i 

I9S.8 

61 

I4I.8 

3i 

87.8 

I 

33-8 

9° 

194. 

60 

I4O. 

30 

86. 

0 

32. 

89 

192.  2 

59 

138.2 

29 

84.2 

—  I 

30.2 

88 

190.4 

58 

136.4 

28 

82.4 

2 

28.4 

8? 

188.6 

57 

134.6 

27 

80.6 

3 

26.6 

86 

186.8 

56 

132.8 

26 

78.8 

4 

24.8 

85 

185- 

55 

I3I- 

25 

77- 

5 

23- 

84 

183.2 

54 

129.  2 

24 

75-2 

6 

21.  2 

83 

181.4 

53 

127.4 

23 

73-4 

7 

19.4 

82 

179.6 

52 

125.  6 

22 

71.6 

8 

I7.6 

81 

177.8 

5i 

123.8 

21 

69.8 

9 

15-8 

To  convert  degrees  Centigrade  to  degrees  Fahrenheit: 
(C°  X  9)  4-  5  and  add  32  =  F°. 
To  convert  degrees  Fahrenheit  to  degrees  Centigrade : 
(F°  -  32)  X  5  -  9  =  C°. 

4.    Comparison  of  Relative  Strengths  of  Chemicals. 

loo  parts  by  weight  of  sal  soda  are  equivalent  to  37  parts  of  soda  ash. 
100  parts  of  soda  ash  are  equivalent  to  270  parts  of  sal  soda. 

TOO  parts  of  crystallized  glaubersalt  are  equivalent  to  44  parts  of  calcined 

glaubersalt. 
loo  parts  of  calcined  glaubersalt  are  equivalent  to  227  parts  of  crystallized 

glaubersalt. 


APPENDIX. 


331 


100  parts  of  alum  are  equivalent  in  dyeing  value  to  60  parts  of  aluminium 

sulphate. 
100  parts  of  aluminium  sulphate  are  equivalent  to  170  parts  of  alum. 

100  parts  of  sulphuric  acid  168°  Tw.  correspond  to  220  parts  hydrochloric 

acid  32°  Tw.,  and  to  400  parts  acetic  acid  9°  Tw. 
100  parts  of  hydrochloric  acid  32°  Tw.  correspond  to  45  parts  of  sulphuric 

acid  1 68°  Tw.,  and  to  175  parts  of  acetic  acid  9°  Tw. 
100  parts  of  acetic  acid  9°  Tw.  correspond  to  26  parts  of  sulphuric  acid 

168°  Tw.,  and  to  57  parts  of  hydrochloric  acid  32°  Tw. 

100  parts  of  crystallized  sodium  sulphide  are  equivalent  to  50  parts  of 

concentrated  sodium  sulphide. 
100  parts  of  concentrated  sodium  sulphide  are  equivalent  to  200  parts  of  the 

crystallized. 

.   Tables  Showing  the   Strengths  and    Densities  of   Various 
Solutions. 

SULPHURIC    ACID. 
At  60°  F.  (15°  C.). 


Deg. 
Tw. 

Per  cent. 
Sulphuric 
Acid. 

Deg. 

Tw. 

Per  cent. 
Sulphuric 
Acid. 

Deg. 
Tw. 

Per  cent. 
Sulphuric 
Acid. 

Deg. 

Tw. 

Per  cent. 
Sulphuric 
Acid. 

2 

1-57 

48 

32.28 

94 

56.90 

140 

77.17 

4 

3-°3 

50 

33-43 

96 

57.83 

142 

78.04 

6 

4-49 

52 

34-57 

98 

58.74 

144 

78.92 

8 

5-96 

54 

35-71 

IOO 

59-70 

146 

79.80 

10 

7-37 

56 

36.87 

102 

60.65 

148 

80.68 

12 

8.77 

58 

38-03 

IO4 

61.59 

*5° 

81.56 

14 

10.  19 

60 

39-19 

106 

62.53 

*52 

82.44 

16 

10.90 

62 

40.35 

108 

63-43 

i54 

83-32 

18 

12.99 

64 

41.50 

no 

64.  26 

156 

84.50 

20 

I4«35 

66 

42.  66 

112 

65.08 

158 

85.70 

22 

I5-7I 

68 

43-74 

114 

65.90 

160 

86.90 

24 

17.01 

70 

44.82 

116 

66.71 

162 

88.30 

26 

18.31 

72 

45-88 

118 

67.59 

164 

90.05 

28 

19.  61 

74 

46.94 

120 

68.51 

165 

91.00 

3° 

20.91 

76 

48.50 

122 

69.43 

1  66 

92.  10 

32 

22.  19 

78 

49.06 

124 

70.32 

167 

93-43 

34 

23-47 

80 

50.  ii 

126 

71.  16 

1  68 

95-6o 

36 

24.76 

82 

5i.i5 

128 

71.99 

!68.3* 

97.70 

38 

26.  04 

84 

52-15 

130 

72.82 

168.1 

98.70 

40 

27-32 

86 

53-  " 

132 

73.64 

1  68 

99.20 

42 

28.58 

88 

54-07 

J34 

74.5i 

167.7 

99-95 

44 

20.  84 

90 

er.  03 

136 

7<.  42 

46 

y            T^ 
31        II 

.  yw 
02 

oo      o 
c  C   07 

*»?** 

1^8 

/  o    ^ 
76  30 

*TW 

ox  • 

V^ 

o  j  -  y  / 

*j^ 

IV4  O^ 

*  Sulphuric  acid  of  97.70  per  cent,  has  the  highest  density,  whilst  that  of  the  stronger 
acid  is  slightly  lower. 


332 


DYEING  AND    TEXTILE  CHEMISTRY. 


HYDROCHLORIC    ACID. 
At  60°  F. 


Per  cent. 

Per  cent. 

Per  cent. 

Per  cent. 

Deg. 

Hydro- 

Deg. 

Hydro- 

Deg. 

Hydro- 

Deg. 

Hydro- 

Tw. 

chloric 

Tw. 

chloric 

Tw. 

chloric 

Tw. 

chloric 

Acid. 

Acid. 

Acid. 

Acid. 

I 

I-I5 

ii 

11.18 

21 

20.97 

3i 

30-55 

2 

2.14 

12 

12.  19 

22 

21.92 

32 

3I-52 

3 

3.12 

13 

I3-I9 

23 

22.86 

33 

32-49 

4 

4.13 

14 

14.17 

24 

23.82 

34 

33-46 

5 

5-15 

15 

15.  16 

25 

24.78 

35 

34-42 

6 

6-15 

16 

16.  15 

26 

25-75 

36 

35-39 

7 

7-iS 

17 

I7-I3 

27 

26.70 

37 

36-3i 

8 

8.16 

18 

18.  ii 

28 

27.66 

38 

37-23 

9 

9.  16 

19 

19.06 

29 

28.61 

39 

38.16 

10 

10.  17 

20 

20.01 

3° 

29-57 

40 

39-n 

From  this  table  it  will  be  seen  that  the  degree  Twaddle  indicates  approximately 
the  percentage  of  hydrochloric  acid  in  the  solution. 


ACETIC   ACID. 
At  60°  F. 


Per  cent. 
Acetic 
Acid. 

Deg. 
Tw. 

Per  cent. 
Acetic 
Acid. 

Deg.  Tw. 

Per  cent. 
Acetic 
Acid. 

Deg.  Tw. 

Per  cent. 
Acetic 
Acid. 

Deg. 

Tw. 

5 

J-3 

3° 

8.2 

55 

I3-I 

80 

15.0 

10 

2.8 

35 

9-4 

60 

!3-7 

85 

14.8 

i5 

4-3 

40 

10.5 

65 

14-3 

90 

14-3 

20 

5-7 

45 

11.4 

70 

14.7 

95 

13.2 

25 

7.0 

5° 

12.3 

75 

14.9 

100 

ii.  I 

The  densities  above  11°  Tw.  correspond  to  two  liquids  of  different  strengths. 
To  determine  if  the  solution  corresponds  to  the  stronger  or  the  weaker  acid,  a 
small  quantity  of  water  is  added,  and  the  density  is  again  measured.  If  the  den- 
sity increases  on  addition  of  water  the  acid  is  the  stronger;  whereas  if  it  dimin- 
ishes the  acid  is  the  weaker. 


APPENDIX. 


333 


CAUSTIC    SODA. 
At  60°  F. 


Per  cent. 
Caustic 
Soda. 

Deg. 

Tw. 

Per  cent. 
Caustic 
Soda. 

Deg.  Tw. 

Per  cent. 
Caustic 
Soda. 

Deg.  Tw. 

Per  cent. 
Caustic 
Soda. 

Deg. 

Tw. 

I 

2.4 

16 

36.2 

31 

68.6 

46 

99-8 

2 

4-6 

17 

38.4 

32 

70.2 

47 

101.  6 

3 

7.0 

18 

40.4 

33 

72.6 

48 

103.8 

4 

9.2 

19 

42.6 

34 

74-8 

49 

105.8 

5 

ii.  8 

20 

4S-o 

35 

76.8 

So 

108.0 

6 

14.0 

21 

47.2 

36 

79.0 

5i 

IIO.O 

7 

16.2 

22 

49-4 

37 

81.0 

52 

112.  O 

8 

18.4 

23 

51-6 

38 

83.0 

53 

II4.O 

9 

20.  6 

24 

53-8 

39 

85-2 

54 

116.0 

10 

23.0 

25 

55-8 

40 

87.4 

55 

118.2 

ii 

25.2 

26 

58.0 

4i 

89.4 

56 

120.2 

12 

27.4 

27 

60.0 

42 

91-5 

57 

122.2 

13 

29.  6 

28 

62.0 

43 

93-  6 

58 

124.4 

14 

31-8 

29 

64.2 

44 

95-  6 

59 

126.6 

15 

34-o 

3° 

66.4 

45 

97.6 

60 

128.6 

SODA   ASH. 
At  60°  F. 


Deg. 
Tw. 

Per  cent. 
Sodium 
Carbonate. 

Deg. 
Tw. 

Per  cent. 
Sodium 
Carbonate. 

Deg. 
Tw. 

Per  cent. 
Sodium 
Carbonate. 

Deg. 
Tw. 

Per  cent. 
Sodium 
Carbonate. 

I 

0.47 

9 

4.28 

17 

8.04 

25 

II.  76 

2 

0-95 

10 

4.76 

18 

8-5i 

26 

12.23 

3 

1.42 

ii 

5-23 

19 

8.97 

27 

12.70 

4 

1.90 

12 

5-71 

20 

9-43 

28 

13.16 

5 

2-38 

13 

6.17 

21 

9.90 

29 

I3-63 

6 

2.85 

14 

6.64 

22 

10.37 

30 

14.09 

7 

•i.  33 

1C 

7.  10 

23 

10.87 

8 

O     OO 

3.80 

16 

7-  57 

O 
24 

O 
II.  3O 

/      %J  / 

*  •  O 

334 


DYEING  AND    TEXTILE  CHEMISTRY. 


GLAUBERSALT. 
At  66°  F. 


Per 
cent. 
Glau- 
bersalt. 

Sp.  gr. 

Per  cent. 
Glauber- 
salt. 

Sp.  gr. 

Per  cent. 
Glauber- 
salt. 

Sp.  gr. 

Per 
cent. 
Glau- 
bersalt. 

Sp.  gr. 

I 
2 

3 

4 

6 

7 

I  .  0040 
1.0079 
1.0118 
1.0158 
1.0198 
1.0238 
i  0278 

9 
10 
ii 

12 
13 
14 
ir 

.0358 
.0398 

•0439 
.0479 
.0520 
.0560 
0601 

17 
18 

19 

20 

21 
22 
2? 

1.0683 
1.0725 
.0766 
.0807 
.0849 
.0890 
.  OQ3I 

25 
26 
27 
28 
29 
3° 

•  IOI5 
•1057 

.  IIOO 

.1142 
.1184 
.  1226 

| 

i.  0318 

16 

I   0642 

24 

.  OO7  3 

The  percentage  of  desiccated  (or  calcined)  glaubersalt,  Na^SO^  may  be  obtained 
by  multiplying  the  above  percentages*  of  crystallized  glaubersalt  by  the  factor  0.441. 

COMMON   SALT    (SODIUM   CHLORIDE). 
At  60°  P. 


Per 

Per 

cent. 

Per  cent. 

Per  cent. 

cent. 

Sodium 

Sp.  gr. 

Sodium 

Sp.  gr. 

Sodium 

Sp.  gr. 

Sodium 

Sp.  gr. 

Chlo- 

Chloride. 

Chloride. 

Chlo- 

ride. 

ride. 

I 

.  00725 

8 

•05851 

IS 

.  11146 

22 

•I6755 

2 

.01450 

9 

•  06593 

16 

.11938 

23 

.17580 

3 

.02174 

10 

•07335 

17 

.12730 

24 

.  18404 

4 

.  02899 

ii 

.  08097 

18 

•I3523 

25 

.  19228 

5 

.  03624 

12 

.08859 

19 

•I43I5 

26 

.  20098 

6 

.  04366 

13 

1.09622 

20 

.15107 

26.  4 

•  20433 

7 

1.05108 

14 

1.10384 

21 

.15931 

TANNIC    ACID. 
At  60°  F. 


Per 

Per  cent. 

Per  cent. 

Per 

cent. 
Tannic 
Acid. 

Sp.  gr. 

Tannic 
Acid. 

Sp.  gr. 

Tannic 
Acid. 

Sp.  gr. 

cent. 
Tannic 

Acid. 

Sp.  gr. 

.0 

.0040 

2.  I 

.0084 

3-2 

.0128 

4-3 

.0172 

.  i 

.0044 

2.  2 

.0088 

3-3 

.0132 

4.4 

.0176 

.2 

.0048 

2-3 

.0092 

3-4 

.0136 

4-5 

.0180 

•3 

.0052 

2.4 

.0096 

3-5 

.0140 

4.6 

.0184 

•4 

.0056 

2-5 

.OIOO 

3-6 

.0144 

4-7 

.0188 

•  5 

.0060 

2.6 

.0104 

3-7 

.0148 

4.8 

.0192 

.6 

.0064 

2.7 

.0108 

3-8 

.0152 

4-9 

.0196 

•7 

.0068 

2.8 

.0112 

3-9 

.0156 

5-o 

.0200 

.8 

OO72 

2    O 

.  01  16 

4O 
.  V-r 

•  .  0160 

Q 

.  w  i  ^ 
OO76 

m  •  y 
30 

.  OI2O 

4.    I 
'    x 

.  0164 

•  y 

2.  O 

,w/\j 
.  0080 

3T 

I  .  0124 

42 

.0168 

'    •*• 

..  & 

APPENDIX. 


335 


BLEACHING    POWDER    (CHLORIDE   OF    LIME) 
At  60°  F. 


Density. 

Available  chlorine. 

Sp.  gr. 

Tw.  deg. 

Per  litre. 

Per  gallon. 

•"55 

23.1 

Grains. 
71.79 

Ozs. 
II 

Grains. 
213 

.1150 

23 

71-5° 

II 

193 

.1105 

22.1 

68.66 

IO 

431 

.1100 

22 

68.00 

IO 

385 

.  1060 

21.  2 

65-33 

IO 

198 

.  1050 

21 

64.50 

IO 

140 

.  IOOO 

2O 

61.  17 

9 

346 

.0950 

.0900 

19 

18 

58.33 
55-  18 

146 
363 

.0850 

17 

52.27 

8 

159 

.0800 

16 

48.96 

7 

365 

.0750 

15 

45-70 

7 

137 

.0700 

14 

42.31 

6 

337 

.0650 

13 

38-71 

6 

85 

.0600 

12 

35-8i 

5 

320 

•  0550 

II 

32.68 

5 

101 

.0500 

10 

29.41 

4 

309 

.0450 

9 

26.  62 

4 

"3 

.0400 

8 

23-75 

3 

35i 

•  0350 

7 

20.44 

3 

119 

.0300 

6 

17.36 

2 

340 

.0250 

5 

14.47 

2 

137 

.0200 

4 

11.44 

I 

362 

.0150 

3 

8.48 

I 

157 

.  OIOO 

2 

s  «c8 

•2QT 

1  .  00*50 

I 

D.  y 

2    71 

oyA 

IOO 

I  .  0025 

i 

*  .  i  j. 
1.40 

*y** 

98 

PROPORTIONS  OF  CHLORINE  IN  WEAK  SOLUTIONS 
OF   BLEACHING   POWDER. 


Deg.  Tw. 

Effective  chlorine, 
grams  per  litre. 

3 

8.48 

Jl 

2.05 

i 

2.71 

1 

4.15 

336 


DYEING  AND    TEXTILE   CHEMISTRY. 


6.  —  Tables  for  Calculations  in  Dyeing. 

PERCENTAGE  OP  DYESTUFF  CORRESPONDING  TO  GRAMS  PER  100  KILOS, 
AND    POUNDS    PER  100  POUNDS    OF    GOODS. 


Per 
cent. 

Per  100 
kilo. 

Per  100  Ibs. 

Per 
cent. 

Per  loo 
kilo. 

Per  loo  Ibs. 

Per 
cent. 

Per  loo 
kilo. 

Per  loo  Ibs. 

gms. 

Ib.  oz.  grns. 

gms. 

Ib.  oz.  grns. 

gms. 

Ib.  oz.  grns. 

0.  001 

I 

7 

O.  29 

290 

4   280 

o.  65 

650 

10   175 

O.  OO2 

2 

14 

0.30 

300 

4   35° 

0.66 

660 

10   245 

0.003 

3 

21 

0.31 

310 

4   420 

o.  67 

670 

10   315 

o.  004 

4 

28 

0.32 

320 

5    53 

0.68 

680 

10   385 

o.  005 

5 

35 

330 

5   123 

0.69 

690 

ii    18 

0.006 

6 

42 

0-34 

340 

5   193 

o.  70 

700 

ii    88 

o.  007 

0.008 

8 

49 
I6 

°-35 
o.  36 

3f 
360 

5   263 
5   333 

0.7! 

0.72 

710 
720 

n   158 
ii   228 

o.  009 

9 

63 

o-37 

37° 

5   403 

o-73 

730 

n   298 

O.  OI 

10 

70 

0.38 

380 

6    35 

0.74 

740 

ii   368 

0.02 

20 

140 

o-39 

390 

6   105 

0-75 

750 

12 

0.03 

.30 

210 

o.  40 

400 

6   175 

o.  76 

76o 

12     70 

o.  04 

40 

280 

0.41 

410 

6   245 

0.77 

770 

12    140 

0.05 

50 

35° 

0.42 

420 

6   315 

0.78 

78o 

12    210 

o.  06 

60 

420 

0-43 

43° 

6   385 

o-79 

790 

12    280 

0.07 
0.08 

£ 

53 
123 

0.44 
0-45 

440 
45° 

7    18 
7    88 

0.80 
0.81 

800 
810 

12   35° 

12    42O 

o.  09 

90 

o.  46 

460 

7   158 

0.82 

820 

i3    53 

O.  IO 

IOO 

263 

0.47 

470 

7   228 

0.83 

830 

13   123 

O.  II 

no 

333 

0.48 

480 

7   298 

0.84 

840 

13   193 

O.  12 

I2O 

403 

0.49 

49° 

7   368 

0.85 

850 

13   263 

O.I3 

130 

2    35 

0.50 

500 

8   ... 

0.86 

860 

13   333 

0.14 

140 

2    106 

0.51 

8    70 

0.87 

870 

13   403 

0.15 

15° 

2   176 

0.52 

520 

8   140 

0.88 

880 

i4    35 

o.  16 

160 

2    246 

o-53 

53° 

8    210 

0.89 

890 

14   105 

0.17 

170 

2    3I6 

540 

8   280 

0.90 

900 

i4   i75 

o.  18 

180 

2    386 

o-55 

550 

8   350 

0.91 

910 

14   245 

o.  19 

190 

3    18 

0.56 

56o 

8   420 

0.92 

920 

14   315 

o.  20 

200 

3    88 

o.  57 

57° 

9    53 

o-93 

93° 

14   385 

O.  21 

2IO 

3   158 

0.58 

580 

9   123 

0.94 

940 

15  £ 

O.  22 

22O 

3   229 

0-59 

590 

9   193 

0-95 

95° 

15    88 

0.23 

230 

3   299 

o.  60 

600 

9   263 

0.96 

960 

15   158 

o.  24 

240 

3   369 

o.  61 

610 

9   333 

0.97 

970 

15   228 

0.25 

250 

4 

o.  62 

620 

9   403 

0.98 

980 

15   298 

o.  26 

200 

4    7° 

0.63 

630 

10    35 

0.99 

990 

15   368 

0.27 

270 

4   140 

o.  64 

640 

10   105 

i 

i  Kilo 

i 

0.28 

280 

4   210 

i  Ib.  =  1 6  oz.  =  7000  grains  =  454  grams, 
i  oz.  =  437 i  grains  =  28.349  grams, 
i  gram  =  15.43  grains. 


APPENDIX. 


337 


COMPARISON  OF  DYE-TESTS  WITH  TEST-SKEINS  OP  5  GRAMS  (77  GRAINS) 
AND  PRACTICAL  DYEING  OF  100  POUNDS  MATERIAL. 

The  standard  solutions  for  the  dye-tests  contain  i  gram  of  dyestuff  dissolved  in  i  litre 
of  water. 


For  5 
grams 
samples. 

Equiva- 
lent per- 
centage. 

Equivalent  per 
100  Ibs. 

For  5 
grams 
samples. 

Equiva- 
lent per- 
centage. 

Equivalent  per 
100  Ibs. 

ccm. 

per  cent. 

Ib.   oz.    grns. 

ccm. 

per  cent. 

Ib.  oz.    grns. 

I 

O.O2 

140 

47 

0.94 

15     i8 

2 

O.O4 

\    62 

48 

0.96 

15    158 

3 

O.06 

\    202 

49 

0.98 

iSl   179 

4 

0.08 

I     I23 

5° 

I.OO 

5 

O.  IO 

il    44 

5i 

1.02 

i        140 

6 

0.  12 

i$   184 

52 

I.O4 

i     1    62 

7 

o.  14 

2     105 

53 

I.  06 

I       $    202 

8 

o.  16 

2|     27 

54 

I.  08 

I     I     123 

9 

0.18 

2$    167 

55 

I.  IO 

i    il    44 

10 

o.  20 

3     88 

56 

I.  12 

i    X'i   184 

ii 

O.  22 

3l    9 

57 

I.  14 

I     2     IO5 

12 

9.24 

3l   J99 

58 

1.16 

I     2$     27 

13 

o.  26 

4    7° 

59 

1.18 

I     2$    l67 

14 

0.28 

4    210 

60 

I.  20 

i    3    88 

15 

o.  30 

4$   I32 

61 

I.  22 

i    3l    9 

16 

0.32 

5     53 

62 

1.24 

i    31   149 

17 

0.34 

5    i93 

63 

1.26 

i    4     70 

18 

0.36 

5l   "4 

64 

1.28 

i    4    210 

19 

0.38 

6    35 

65 

I.30 

i    4l   I32 

20 

0.40 

6    175 

66 

1.32 

i    5    53 

21 

o.  42 

61   97 

67 

i-34 

i    5    i93 

22 

0.44 

7    18 

68 

1.36 

i    Si   "4 

23 

o.  46 

7    158 

69 

1.38 

i    6    35 

24 

0.48 

7$   79 

70 

1.40 

i    6    175 

25 

o.  50 

8     oo 

7i 

1.42 

i    61   97 

26 

0.52 

8    140 

72 

1.44 

i    7    13 

27 

0.54 

8}    62 

73 

1.46 

i    7    158 

28 

o.  56 

8$    202 

74 

1.48 

i    7l    79 

29 

0.58 

9    I23 

75 

1.50 

i    8 

30 

o.  60 

9l    44 

76 

1.52 

i    8   K-i4o 

31 

o.  62 

9l   l84 

77 

i-54 

i    8$    62 

32 

o.  64 

10    105 

78 

1-56 

i    8$   202 

33 

0.66 

10$    27 

79 

i-58 

i    9    123 

34 

0.68 

io|   167 

80 

i.  60 

i    9l    44 

35 

o.  70 

ii     88 

81 

1.62 

i    9!   184 

36 

o.  72 

"I    9 

82 

i.  64 

i   10    105 

37 

0.74 

nl   149 

83 

1.66 

i   10$    27 

38 

o.  76 

12      70 

84 

1.68 

i   10$   167 

39 

0.78 

12      210 

85 

1.70 

i   ii     88 

40 

0.80 

I2l    132 

86 

1.72 

i   11$    9 

4i 

0.82 

13       53 

87 

i-74 

i   n$   149 

42 

0.84 

13    J93 

88 

1.76 

I    12       70 

43 

0.86 

13!   IJ4 

89 

1.78 

I    12     2IO 

44 

0.88 

14     35 

90 

i.  80 

I    12$    132 

45 

0.90 

14    175 

9i 

1.82 

I    13      53 

46 

0.92 

i4l    97 

92 

1.84 

I    13     193 

338 


DYEING   AND    TEXTILE  CHEMISTRY. 


COMPARISON  OP  DYE-TESTS.  —  Continued. 


For  5 
grams 
samples. 

Equiva- 
lent per- 
centage. 

Equivalent  per 
100  Ibs. 

For  5 
grams 
samples. 

Equiva- 
lent per- 
centage. 

Equivalent  per 
ICQ  Ibs. 

ccm. 

per  cent. 

Ib.   oz.    grns. 

ccm. 

per  cent. 

Ib.   oz.    grns. 

93 

.86 

I    13$   114 

147 

2.94 

2    15     18 

94 

.88 

.   14    35 

148 

2.96 

2    IS     IS8 

95 

.90 

14    175 

149 

2.98 

2    15$    179 

96 

.92 

14$    97 

ISO 

3.00 

3 

97 

•94 

15     18 

3.02 

3    o    140 

98 

.96 

15    158 

152 

3-°4 

3     $    62 

99 

1.98 

i5i    79 

153 

3.06 

3       $    202 

IOO 

2.OO 

2 

154 

3.08 

3    !    I23 

101 

2.  O2 

2           I4O 

155 

3.10 

3    i$    44 

102 

2.04 

2       $     62 

156 

3.12 

3    i$   184 

I03 

2.o6 

2       |    202 

J57 

3-14 

3    2    105 

104 

2.08 

2     I     123 

158 

3    2$    27 

I05 

2.  10 

2    i$    44 

3-  18 

3    2$   167 

106 

2.  12 

2      1$    184 

160 

3-20 

3    3     88 

107 

2.14 

2     2     IO5 

161 

3-22 

3    3$    9 

1  08 

2.!6 

2      2$     27 

*l62 

3-24 

109 

2.l8 

2     2$    167 

163 

3-26 

3    4     70 

no 

2.  20 

2    3    88 

164 

3.28 

3    4    210 

in 

2.  22 

2   3i    9 

165 

3-30 

3    4$   132 

112 

2.24 

2    3$   149 

1  66 

3-32 

3    5    53 

H3 

2.26 

2    4     70 

167 

3-34 

3    5    i93 

114 

2.28 

2     4     210 

1  68 

3.36 

3    5$   ii4 

"5 

2.30 

2    4$   132 

169 

3.38 

3    6    35 

116 

2.32 

2    5    53 

170 

3-40 

3    6    175 

117 

2-34 

2    5    193 

171 

3-42 

3    6i   97 

118 

2.36 

172 

3-44 

3    7    18 

119 

2.38 

2    6    35 

173 

3-  46 

3    7    158 

120 

2.40 

2    6    175 

3-48 

3    7i    79 

121 

2.42 

2    6$   97 

175 

3-5° 

3    8 

122 

2.44 

2    7    185 

176 

3-52 

3    8    140 

123 

2.46 

2    7    158 

177 

3-54 

3    8$    62 

124 

2.48 

2    7i   79 

178 

3.56 

3    8$   202 

125 

2.50 

2     8 

3.58 

3    9    I23 

126 

2.52 

2    8    140 

1  80 

3.60 

3    9$    44 

127 

2.54 

2     8$     62 

181 

3.62 

3    9$   l84 

128 

2.56 

2      8$    202 

182 

3-64 

3   1°    105 

129 

2.58 

2    9    123 

183 

3.66 

3   i°i    27 

130 

2.  60 

2    9$    44 

184 

3-68 

3   io|   167 

2.62 

2    9$   184 

185 

3-70 

3   ii    88 

132 

2.  64 

2    IO     IO5 

186 

3-72 

3   n$    9 

2.66 

2    10$     27 

187 

3-74 

3   ii  i   149 

134 

2.68 

2    10$    167 

1  88 

3-76 

3   12     70 

2.70 

2   ii    88 

189 

3.78 

3   12    210 

136 

2.72 

2    11$      9 

190 

3.80 

3   12$   132 

2-74 

2    11$    149 

191 

3.82 

3   13     53 

138 

2.76 

2    12      70 

192 

3-84 

3   i3    J93 

2.78 

2    12      210 

193 

3'^ 

3   i3i   H4 

140 

2.80 

2    12$    132 

194 

3.88 

3   14    35 

141 

2.82 

2   13    53 

195 

3-90 

3   14    175 

142 

2.84 

2    13      193 

196 

3-92 

3   i4$    97 

143 

2.86 

2    13$    114 

197 

3-94 

3   T5    l8 

144 

2.88 

2   14    35 

198 

3-96 

3   i5    iS8 

145 

2.90 

2    14      175 

199 

3-98 

3   i5$   79 

146 

2.92 

2   14$    97 

200 

4.00 

4 

APPENDIX.  339 

REDUCTION    OF   GRAMS   TO    OUNCES    PER    100  LBS.    GOODS. 


Ounces 

Ounces 

Ounces 

Grams. 

for  solu- 

Grams . 

for  solu- 

Grams. 

for  solu- 

tion. 

tion. 

tion. 

I 

•35 

II 

3.88 

21 

7.41 

2 

•7i 

12 

4.24 

22 

7.76 

3 

i.  06 

J3 

4-58 

23 

8.12 

4 

1.41 

14 

4-93 

24 

8.47 

5 

1.77 

15 

5-29 

25 

8.82 

6 

2.  12 

16 

5-64 

26 

9.17 

7 

2.47 

I7 

5-99 

27 

9-53 

8 

2.83 

18 

6-34 

28 

9.88 

9 

3.l8 

19 

6.60 

29 

10.  22 

10 

3-53 

20 

7.06 

30 

10.59 

To  use  any  number  of  grams  per  100  pounds  of  goods,  dissolve 

the  corresponding  number  of  ounces  in  above  table  in  10  gallons 

of  water,  and  use  i  gallon  of  this  solution  per  100  pounds  goods. 

FOR  EXAMPLE.     To  use  42  grams  of  dyestuff  per  100  pounds 

goods : 

30  grams  =  10.59  ounces 

10  grams  =    3.53  ounces 

2  grams  =      .71  ounces 

42  grams  =  14.83  ounces 

Therefore,  dissolve  14.83  ounces  of  dyestuff  in  10  gallons  of  water 
and  use  i  gallon  of  the  solution. 

To  Determine  the  Capacity  of  a  Rectangular  Vat.  —  Multiply 
the  length  by  the  breadth  by  the  depth  in  feet  to  obtain  the  cubic 
contents;  then  multiply  this  number  by  yj  to  obtain  the  capacity 
in  gallons  (United  States). 

Or,  multiply  the  length  by  the  breadth  by  the  depth  in  inches, 
and  divide  the  result  by  231  to  obtain  the  capacity  in  gallons. 

To  Determine  the  Capacity  of  a  Round  Vat.  —  Multiply  the 
diameter  in  feet  by  itself;  multiply  the  result  by  the  factor  0.7854, 
and  then  by  the  depth  in  feet;  finally  multiply  this  result  by  7!  to 
obtain  the  capacity  in  gallons. 

Or,  multiply  the  diameter  in  inches  by  itself,  then  multiply  by 
0.7854,  and  then  by  the  depth  in  inches.  Divide  the  result  by 
231  to  obtain  the  capacity  in  gallons. 


340 


DYEING   AND    TEXTILE   CHEMISTRY. 


REDUCTION  OF  GRAMS  PER  KILOGRAM  OP  GOODS  TO  OUNCES 
PER   100  POUNDS  OF  GOODS. 


Grams  per 
kilo. 

Ounces 
per  100 
Ibs. 

Grams  per 
kilo. 

Ounces 
per  100 
Ibs. 

Grams  per 
kilo. 

Ounces 
per  100 
Ibs. 

I 

1.6 

18 

28.8 

35 

56.O 

2 

3-2 

19 

30-4 

36 

57.6 

3 

4.8 

20 

32.0 

37 

59-2 

4 

6.4 

21 

33-6 

38 

60.8 

5 

8.0 

22 

35-2 

39 

62.  4 

6 

9.6 

23 

36.8 

40 

64.0 

7 

II.  2 

24 

38-4 

41 

65.6 

8 

12.8 

25 

40.0 

42 

67.2 

9 

14.4 

26 

41.  6 

43 

68.8 

10 

16.0 

27 

43-2 

44 

70.4 

ii 

17.6 

28 

44-8 

72.0 

12 

19.2 

29 

46.4 

46 

73-6 

13 

20.8 

30 

48.0 

47 

75-2 

14 

22.4 

31 

49-6 

48 

76.8 

15 

24.0 

32 

51.2 

49 

78.4 

16 

25.6 

33 

52.8 

5° 

80.0 

17 

27.  2 

24 

54-  4 

*  / 

/  • 

o  • 

To  convert  grams  per  kilo,  into  ounces  per  100  Ibs.,  multiply  by  the  factor  1.6. 

REDUCTION  OF  FRACTIONAL  PERCENTAGES  TO  OUNCES  PER  100  POUNDS 

OF  GOODS. 


Per 
cent. 

Ounces  per 
100  Ibs. 
goods. 

Per 
cent. 

Ounces  per 
100  Ibs. 
goods. 

Per 
cent. 

Ounces  per 
100  Ibs. 
goods. 

Per 
cent. 

Ounces  per 
100  Ibs. 
goods. 

| 

8.00 

} 

2.OO 

£ 

7.28 

. 

II.  II 

1 

6.  oo 

A 

8-73 

iir 

12.31 

| 

lo.*  66 

f 

IO.OO 

14.00 

£ 

10.  19 
ii.  64 

it 

13-54 
14-77 

£ 

4.00 

12.  OO 

I 

1.77 

fi 

13.09 

¥ 

1.14 

4 

3-20 

6.40 
o.  60 

! 

3-55 
7.11 
8.88 
12.44 

1 

i-34 
6.66 

3-44 
5-72 
10.  29 

10-57 

I 

y.    v^r 

12.  80 

I 

14.22 

\l 

14.66 

if 

14.86 

^ 

2.66 

yV 

i.  60 

TV 

1.07 

I 

13.3° 

A 

4.80 

A 

1.23 

2.13 

To 

ii.  20 

* 

2.46 

T^Jr 

4.27 

2.  29 

TG 

14.40 

3-69 

T6T 

6.  40 

4.58 

TT 

4.92 

xV 

7-47 

6.86 

TT 

1.45 

T\ 

6.16 

jV 

8-53 

9-  J5 

A 

2.  9! 

"IT 

7-39 

*i 

n-73 

11  •  43 

"?T 

4-37 

IT 

8.61 

it 

13-87 

13.80 

A 

5-82 

T83 

9.85 

» 

14.96 

APPENDIX. 


341 


REDUCTION  OF    DECIMAL    PERCENTAGES    TO  OUNCES  PER   100  POUNDS 

OF  GOODS. 


Per 

Ounces  per 
100  Ibs. 

Per 

Ounces  per 
too  Ibs. 

Per 

Ounces  per 
100  Ibs. 

Per 

Ounces  per 
100  Ibs. 

cent. 

goods. 

cent. 

goods  . 

cent. 

goods. 

cent. 

goods. 

.  10 

I.  60 

•35 

5.60 

.60 

9.  60 

•85 

13.60 

•!5 

2.40 

.40 

6.40 

•65 

10.40 

.90 

14.40 

.  20 

3.20 

•45 

7.20 

.70 

11.20 

•95 

15.20 

•25 

4.00 

•5° 

8.00 

•75 

12.  OO 

I.  00 

1  6.  00 

30 

4.  80 

.  HH 

8.80 

.80 

12.  80 

REDUCTION    OF    DECIMAL    PARTS    OF    POUNDS    TO    OUNCES. 


Lbs. 

Oz. 

Lbs. 

Oz. 

Lbs. 

Oz. 

Lbs. 

Oz. 

.01 

.16 

.14 

2.24 

•27 

4-32 

.40 

6.40 

.02 

•32 

•!5 

2.40 

.28 

4.48 

.41 

6.56 

•°3 

.48 

.16 

2.56 

.29 

4.64 

.42 

6.72 

.04 

.64 

•I? 

2.72 

•3° 

4.80 

•43 

6.88 

•°5 

.80 

.18 

2.88 

•3i 

4.96 

•44 

7.04 

.06 

.96 

.19 

3-°4 

•32 

5.12 

•45 

7.20 

.07 

I.  12 

.  20 

3-20 

•33 

5-28 

.46 

7.36 

.08 

1.28 

.21 

3.36 

•34 

5-44 

•47 

7-52 

.09 

1.44 

.  22 

3-52 

•35 

5-6o 

•  48 

7.68 

.  10 

I.  60 

•23 

3.68 

•36 

5-76 

•49 

7-84 

.11 

I.76 

.24 

3-84 

•37 

5-92 

•5° 

8.00 

.12 

I.  O2 

.  2< 

4.  oo 

•  ^8 

6.08 

•13 

A  *  y-*- 

2.08 

3 
.26 

4.  16 

o 
•39 

6.  24 



REDUCTION  OF   DECIMAL  PERCENTAGES  OF  GALLONS  TO   QUARTS  AND 

PINTS. 


Gals. 

Qts. 

Pts. 

Gals. 

Qts. 

Pts. 

Gals. 

Qts. 

Pts. 

oc 

4 

.  40 

i 

IT 

.  7H 

•? 

TO 

} 

.  4H 

i 

ll 

.80 

•j 

If 

It 

.  HO 

2 

,8< 

•? 

2O 

I  » 

•  HH 

2 

£ 

.  OO 

•j 

I' 

•25 
.  3O 

i 
i 

i 

.60 
.65 

2 
2 

1^ 

•95 

I.  OO 

3 

4 

v  • 

•yf 

i 

4 

.    7O 

2 

i4 

342 


DYEING  AND    TEXTILE  CHEMISTRY. 


REDUCTION   OF   LITRES   PER   KILOGRAM   OF   GOODS  TO    GALLONS 
100    POUNDS    OF    GOODS. 


PER 


Litres 
'     per 
kilo. 

Gallons 
per  100 
pounds. 

Litres  per 
kilo. 

Gallons 
per  100 
pounds. 

Litres  per 
kilo. 

Gallons 
per  100 
pounds. 

Litres 
per 
kilo. 

Gallons 
per  too 
pounds  . 

I 

11.99 

14 

167.88 

27 

323.78 

4° 

479.68 

2 

23.98 

15 

179.88 

28 

335-77 

41 

491.67 

3 

35-97 

16 

191.87 

29 

347-76 

42 

503.66 

4 

47-96 

17 

203.86 

3° 

359-76 

43 

5I5-65 

5 

18 

215-85 

371-75 

44 

527-64 

6 

7i-95 

19 

227.84 

32 

383-  74 

45 

539-64 

7 

83-94 

20 

239.84 

33 

395-73 

46 

55I-63 

8 
9 

95-93 
107.92 

21 
22 

25I-83 
263.82 

34 
35 

407.72 
419.72 

47 
48 

563.62 
575-6i 

10 

119.92 

23 

275.81 

36 

431-  71 

49 

587-60 

ii 

131.91 

24 

287.80 

37 

443-7° 

5° 

599-60 

12 

I  A3    OO 

2  C 

299.80 

38 

i  -  -     A/-\ 

A  £}.£  .  \-J\J 

J55  -89 

26 

467  68 

13 

311-79 

39 

T-"/  '  w 

REDUCTION    OF    GRAMS    PER    LITRE    TO    OUNCES    PER    GALLON. 


Grams 
per 
litre. 

Ounces  per 
gallon. 

Grams  per 
litre. 

Ounces  per 
gallon. 

Grams  per 
litre. 

Ounces  per 
gallon. 

Grams 
per 
litre. 

Ounces  per 
gallon. 

I 

•13 

9 

I.  20 

17 

2.  26 

25 

3-33 

2 

.26 

IO 

i-33 

18 

2.40 

26 

3-46 

3 

.40 

ii 

1.46 

19 

2-53 

27 

3-6o 

4 

•53 

12 

i.  60 

20 

2.66 

28 

3-73 

5 

.66 

X3 

!-73 

21 

2.80 

29 

3-86 

6 

.80 

14 

1.86 

22 

2-93 

3° 

4.00 

•tj 

2    OO 

o  'y 

306 

I 

•93 
i   06 

16 

24 

.uu 
320 

To  convert  grams  per  litre  into  ounces  per  gallon,  multiply  by  the  factor  0.133. 


APPENDIX. 


343 


PERCENTAGE  TABLES. 


Per 
cent. 

For  10  pounds. 

For  50  pounds. 

For  too  pounds. 

10.  0 

9.0 
8.0 
7.0 

I  Ib. 
14  oz.  175  grains 
12  oz.  350  grains 
ii  oz.  87  grains 

5  Ibs. 
4i  Ibs. 
4  Ibs. 
3i  Ibs. 

10  Ibs. 
9  Ibs. 
8  Ibs. 
7  Ibs. 

6.0 

9  oz.  263  grains 

3  Ibs. 

6  Ibs. 

5-o 
4.0 

3-° 

2.O 

8  oz. 
6  oz.  175  grains 
4  oz.  350  grains 
3  oz.  88  grains 

2^  Ibs. 
2   Ibs. 

i*  Ibs. 

I  Ib. 

5  Ibs. 
4  Ibs. 
3  Ibs.   • 
2  Ibs. 

I  .0 

i  oz.  263  grains 

8  oz. 

i  Ib. 

0.99 
0.98 
0.97 
0.96 

i  oz.  256  grains 
i  oz.  249  grains 
i  oz.  242  grains 
i  oz.  235  grains 

7  oz.  403  grains 
7  oz.  368  grains 
7  oz-  333  grains 
7  oz.  298  grains 

15  oz.  368  grains 
15  oz.  298  grains 
15  oz.  228  grains 
15  oz.  158  grains 

°-95 

i  oz.  228  grains 

7  oz.  263  grains 

15  oz.  88  grains 

0.94 

o-93 
0.92 
0.91 

i  oz.  221  grains 
i  oz.  214  grains 
i  oz.  207  grains 
i  oz.  200  grains 

7  oz.  228  grains 
7  oz.  193  grains 
7  oz.  158  grains 
7  oz.  123  grains 

15  oz.  1  8  grains 
14  oz.  385  grains 
14  oz.  315  grains 
14  oz.  245  grains 

0.90 

i  oz.  193  grains 

7  oz.  88  grains 

14  oz.  175  grains 

0.87 
0.86 

i  oz.  1  86  grains 
i  oz.  179  grains 
i  oz.  172  grains 
i  oz.  165  grains 

7  oz.  53  grains 
7  oz.  1  8  grains 
6  oz.  420  grains 
6  oz.  385  grains 

14  oz.  105  grains 
14  oz.  35  grains 
13  oz.  403  grains 
J3  oz-  333  grains 

0.85 

i  oz.  158  grains 

6  oz.  350  grains 

13  oz.  263  grains 

0.84 
0.83 
0.82 
0.81 

i  oz.  151  grains 
i  oz.  144  grains 
i  oz.  137  grains 
i  oz.  130  grains 

6  oz.  315  grains 
6  oz.  280  grains 
6  oz.  245  grains 
6  oz.  210  grains 

13  oz.  193  grains 
13  oz.  123  grains 
13  oz.  53  grains 
12  oz.  420  grains 

0.80 

i  oz.  123  grains 

6  oz.  175  grains 

12  oz.  350  grains 

0.79 
0.78 
0.77 
0.76 

i  oz.  116  grains 
i  oz.  109  grains 
i  oz.  1  02  grains 
i  oz.  95  grains 

6  oz.  140  grains 
6  oz.  105  grains 
6  oz.  70  grains 
6  oz.  35  grains 

12  oz.  280  grains 
12  oz.  210  grains 
12  oz.  140  grains 
12  oz.  70  grains 

o-75 

i  oz.  88  grains 

6  oz. 

12  OZ. 

0.74 

°-73 
0.72 
0.71 

i  oz.  8  1  grains 
i  oz.  74  grains 
i  oz.  67  grains 
i  oz.  60  grains 

5  oz.  403  grains 
5  oz.  368  grains 
5  oz.  333  grains 
5  oz.  298  grains 

ii  oz.  368  grains 
ii  oz.  298  grains 
ii  oz.  228  grains 
ii  oz.  158  grains 

0.70 

i  oz.  53  grains 

5  oz.  263  grains 

ii  oz.  88  grains 

344 


DYEING  AND    TEXTILE  CHEMISTRY. 


PERCENTAGE    TABLES. 


Per 

cent. 

For  10  pounds. 

For  50  pounds. 

For  100  pounds. 

o.  69 
0.68 
o.  67 
0.66 

i  oz.  46  grains 
i  oz.  39  grains 
i  oz.  32  grains 
i  oz.  25  grains 

5  oz.  228  grains 
5  oz.  193  grains 
5  oz.  158  grains 
5  oz.  123  grains 

ii  oz.  18  grains 
10  oz.  385  grains 
10  oz.  315  grains 
10  oz.  245  grains 

0.65 

i  oz.  1  8  grains 

5  oz.  88  grains 

10  oz.  175  grains 

o.  64 
o.  63 
o.  62 
0.61 

i  oz.  ii  grains 
i  oz.   4  grains 
434  grains 
427  grains 

5  oz.  53  grains 
5  oz.  1  8  grains 
4  oz.  420  grains 
4  oz.  385  grains 

10  oz.  105  grains 
10  oz.  35  grains 
9  oz.  403  grains 
9  oz.  333  grains 

o.  60 

420  grains 

4  oz.  350  grains 

9  oz.  263  grains 

o-59 
0.58 

o-57 
0.56 

413  grains 
406  grains 
399  grains 
392  grains 

4  oz.  315  grains 
4  oz.  280  grains 
4  oz.  245  grains 
4  oz.  210  grains 

9  oz.  193  grains 
9  oz.  123  grains 
9  oz-  53  grains 
8  oz.  420  grains 

o-SS 

385  grains 

4  oz.  175  grains 

8  oz.  350  grains 

0-54 
o-53 
0.52 
0.51 

378  grains 
371  grains 
364  grains 
357  grains 

4  oz.  140  grains 
4  oz.  105  grains 
4  oz.  70  grains 
4  oz.  35  grains 

8  oz.  280  grains 
8  oz.  210  grains 
8  oz.  140  grains 
8  oz.  70  grains 

o.  50 

350  grains 

4  oz. 

8  oz. 

0.49 
0.48 
0.47 
0.46 

343  grains 
336  grains 
329  grains 
322  grains 

3  oz.  403  grains 
3  oz.  368  grains 
3  oz-  333  grains 
3  oz.  298  grains 

7  oz.  368  grains 
7  oz.  298  grains 
7  oz.  228  grains 
7  oz.  158  grains 

0-45 

315  grains 

3  oz.  263  grains 

7  oz.  88  grains 

0.44 

0.43 
0.42 
0.41 

308  grains 
301  grains 
294  grains 
287  grains 

3  oz.  228  grains 
3  oz.  193  grains 
3  oz.  158  grains 
3  oz.  123  grains 

7  oz.  i  8  grains 
6  oz.  385  grains 
6  oz.  315  grains 
6  oz.  245  grains 

o.  40 

280  grains 

3  oz.  88  grains 

6  oz.  175  grains 

°-39 
0.38 

0-37 
o.  36 

2  73  grains 
266  grains 
259  grains 
252  grains 

3  oz.  53  grains 
3  oz.  i  8  grains 
2  oz.  420  grains 
2  oz.  385  grains 

6  oz.  105  grains 
6  oz.  35  grains 
5  oz.  403  grains 
5  oz.  333  grains 

o-35 

245  grains 

2  oz.  350  grains 

5  oz.  263  grains 

0-34 
°-33 
0.32 
0.31 

238  grains 
231  grains 
224  grains 
217  grains 

2  oz.  315  grains 
2  oz.  280  grains 
2  oz.  245  grains 
2  oz.  210  grains 

5  oz.  193  grains 
5  oz.  123  grains 
5  oz.  53  grains 
4  oz.  420  grains 

0.30 

210  grains 

2  oz.  175  grains 

4  oz.  350  grains 

APPENDIX. 
PERCENTAGE    TABLES. 


345 


Per 

cent. 

For  10  pounds. 

For  50  pounds. 

For  100  pounds. 

o.  29 

0.28 
0.27 

o.  26 

203  grains 
196  grains 
189  grains 
182  grains 

2  oz.  140  grains 
2  oz.  105  grains 
2  oz.  70  grains 
2  oz.  35  grains 

4  oz.  280  grains 
4  oz.  210  grains 
4  oz.  140  grains 
4  oz.  70  grains 

0.25 

175  grains 

2  OZ. 

4  oz. 

o.  24 

0.23 

0.  22 
0.  21 

i  68  grains 
161  grains 
154  grains 
147  grains 

i  oz.  403  grains 
i  oz.  368  grains 
i  oz.  333  grains 
i  oz.  298  grains 

3  oz.  368  grains 
3  oz.  298  grains 
3  oz.  228  grains 
3  oz.  158  grains 

0.  20 

140  grains 

i  oz.  263  grains 

3  oz.  88  grains 

o.  19 
o.  18 
0.17 
o.  16 

133  grains 
126  grains 
119  grains 
112  grains 

i  oz.  228  grains 
i  oz.  193  grains 
i  oz.  158  grains 
i  oz.  123  grains 

3  oz.  1  8  grains 
2  oz.  385  grains 
2  oz.  315  grains 
2  oz.  245  grains 

0.15 

105  grains 

i  oz.  88  grains 

2  oz.  175  grains 

o.  14 
0.13 

0.  12 

O.  II 

98  grains 
91  grains 
84  grains 
77  grains 

i  oz.  53  grains 
i  oz.  1  8  grains 
420  grains 
385  grains 

2  oz.  105  grains 
2  oz.  35  grains 
i  oz.  403  grains 
i  oz-  333  grains 

0.  10 

70  grains 

350  grains 

i  oz.  263  grains 

O.09 
0.08 

o.  07 
0.06 

63  grains 
56  grains 
49  grains 
42  grains 

315  grains 
280  grains 
245  grains 
210  grains 

i  oz.  193  grains 
i  oz.  123  grains 
i  oz.  53  grains 
420  grains 

0.05 

35  grains 

175  grains 

350  grains 

0.04 

0.03 

O.02 

O.OI 

28  grains 
21  grains 
14  grains 
7  grains 

140  grains 
105  grains 
70  grains 
35  grains 

280  grains 
210  grains 
140  grains 
70  grains 

The  following  example  will  illustrate  the  use  of  this  table:   How  much  dyestuff 
would  be  required  for  2.23  per  cent,  on  70  pounds  of  material? 


For  50  Ibs.         2%  equals  i  Ib. 
For  20  Ibs.         2%  equals  6  oz.  176  grains 

For  50  Ibs.  o.  23%  equals  i  oz.  368  grains 

For  20  Ibs.  o.  23%  equals  322  grains 


For  70  Ibs.     2.  23%  equals  i  Ib.  8  oz.  429  grains 


346 


DYEING   AND    TEXTILE   CHEMISTRY. 


TABLE    SHOWING    THE    AMOUNTS    OF    SODIUM    NITRITE,    ACID,    AND 
DEVELOPER    REQUIRED    FOR    DIAZOTIZING. 


Dyestuff. 
x    Per  cent. 

Sodium  nitrite. 
Per  cent. 

Sulphuric  acid 
i68°Tw. 
Per  cent. 

Or  hydrochloric 
acid  in  place  of 
sulphuric. 
Per  cent. 

Developer. 
Per  cent. 

i 

I 

2 

3 

o   5 

1} 

2  J 

3f 

oie 

Ji 

1  1 

3 

4i 

0.7 

2 

IJ 

34 

s! 

0.8 

2$ 

2 

4 

6 

0.9 

3 

2 

4 

6 

i. 

3* 

2< 

5 

7$ 

i. 

4 

2i 

5 

7i 

i. 

4* 

2! 

5 

7} 

i. 

5 

2! 

5 

7* 

i. 

These  figures  are  not  supposed  to  be  in  exact  chemical  propor- 
tion, but  for  practical  reasons  a  sufficient  excess  of  developer  is 
prescribed.  Good  results  are  to  be  obtained  from  these  quantities 
only  when  the  proportion  of  dyed  material  to  water  is  i  :  15. 

TABLE    OF    ATOMIC    WEIGHTS    OF    PRINCIPAL    ELEMENTS. 
O  =  16. 


Element. 

Sym- 
bol. 

At.  wt. 

Element. 

Sym- 
bol. 

At.  wt. 

Aluminium  

Al 

27.  i 

Magnesium  

Mg 

24.  36 

Antimony  

Sb 

I2O. 

Manganese 

Mn 

te 

Arsenic 

As 

7t 

IMercury 

He 

2O7 

Barium 

Ba 

1  37   4. 

JMolybdenum 

Mo 

^6- 
06 

Bismuth  .  .    . 

Bi 

XJ/  •  t 
208    C 

Nickel 

Ni 

<8    7 

Boron  

B 

II 

Nitrogen 

N 

UO4, 

Bromine  

Br 

70.  06 

Oxygen  . 

o 

16 

Cadmium  

Cd 

112.  4 

Phosphorus  

P 

U. 

Calcium 

Ca 

do 

Platinum 

Pt 

IO4    8 

Carbon.  .   . 

c 

12 

Potassium 

K 

30    I  ^ 

Cerium  

Ce 

1  4O 

Silicon 

Si 

28    4. 

Chlorine  

Cl 

7ir.  e 

Silver     

Ag 

107.  o? 

Chromium 

Cr 

C2      T 

Sodium 

Na 

2?     QC 

Cobalt 

Co 

CQ 

Strontium 

Sr 

87  6 

Conner    . 

Cu 

6t  6 

Sulphur 

s 

•?2    06 

„  "*T^  
r  luonne  

Fl 

IO 

Tin 

Sn 

3*.  wvy 

118  «; 

Gold  

Au 

107   2 

Titanium  

Ti 

X  3 
48. 

Hydrogen  
Iodine  

H 
I 

I.  01 

126.85 

Tungsten  
Uranium  

W 

u 

184. 
230.  <? 

Iron  .  . 

Fe 

<;6 

Vanadium 

v 

Cl    2 

Lead  

Pb 

5"- 

206  o 

Zinc        .            ... 

Zn 

2 

6c.4 

APPENDIX. 


347 


TABLE    OF    FORMULA    AND    MOLECULAR  WEIGHTS    OF     PRINCIPAL 
CHEMICALS    USED    IN    DYEING. 


Name. 


Acetate  of  alumina 

Acetate  of  ammonia 

Acetate  of  chrome  (basic) 

Acetate  of  chrome  (normal) 

Acetate  of  lime 

Acetate  of  nickel 

Acetate  of  soda 

Acetate  of  tin 

Acetic  acid 

Aectine 

Acid  sodium  sulphate 

Acid  sodium  sulphite 

Alcohol 

Alpha-naphthylamine 

Alum  (potash) 

Aluminium  chloride 

Aluminium  sulpho-acetate 

Ammonia 

Ammonium  chloride 

Ammonium  tin  chloride 

Ammonium  vanadate 

Aniline 

Aniline  salt 

Antimony  fluoride 

Antimony  oxide 

Antimony  salt 

Antimony  sodium  fluoride 

Barium  chloride 

Benzene 

Beta-naphthol 

Bichromate  of  soda 

Bichromate  of  potash 

Bisulphite  of  chrome 

Borax 

Calcium  chloride 

Caustic  lime 

Caustic  soda 

Caustic  potash 

Cerium  chloride 

Chalk 

Chlorate  of  alumina 

Chloride  of  chrome  (basic) 

Chlorate  of  potash 

Chlorate  of  sodium 

Chromate  of  chrome 

Chromate  of  lead. 

Chrome  alum 

Chrome  oxide 

Chromium  nitro-acetate 


Formula. 


A12(C2H302)2 

NH4C2H302 

Cr2(C2H302)4  .  (OH)S 

Cr2(C2H302)6 

Ca(C2H302)2 

Ni(C2H302)2 

NaC2H302.3H20 

Sn(C2H302)2 

CH3  .  COOH 

C3H5(C2H302)3 

NaHSO4 

NaHSO3 

C2H5OH 


A12(S04)3K2S04  .  24  H20 

A12C16 

A12S04(C2H302)4 

NH3 

NH4C1 

SnCl4  .  2  NH4C1 

(NH4)3V04 

C.H.NH, 

C6H5NH2 .  HC1 

SbF3 

Sb203 

SbF3(NH4)2S04 

SbF3NaF 

BaCl2 .  2  H20 

C6H6 

C10H7 .  OH 

Na2Cr207 .  2  H2O 


Cr2(HS03)6 

Na2B4O7  .  10  H2O 

CaCl2 

CaO 

NaOH 

KOH 

CeCl3 

CaCO3 

A12(C103)6 

Cr2Cl2(OH)4 

KC103 

NaC103 

Cr2(Cr04)3 

PbCr04 

Cr2(S04)3K2S04.24H20 

Cr204 

Cr2(N03)3(C2H302)3 


Mol.  wt. 


408 

77 

374 

458 

177 

237 

60 

218 

120 

IO4 

46 

143 
949 
267 
386 

54 
367 
169 

93 
130 
177 

288 

3°9 

219 

244 

78 

144 

298 

295 

59i 

382 

in 

56 

40 

56 

246 
100 
555 
243 
123 
107 
453 

999 
467 


348 


DYEING  AND    TEXTILE  CHEMISTRY. 


TABLE    OF    FORMULA    AND    MOLECULAR    WEIGHTS    OF    PRINCIPAL 
CHEMICALS     USED    IN     DYEING.  — Continued. 


Name. 

Formula. 

Mol.  wt. 

Common-salt  

NaCl 

CQ 

Cupric  chloride  

CuCl2  .  2  H2O 

1  71 

Double  chloride  of  tin 

SnCl4    3  HjO 

7J  A 

Ferric  acetate 

Fe,(CoH,O,). 

466 

Ferric  chloride  .... 

Fe2Cl6 

•12  C 

Ferrous  acetate  

Fe(C,H,Oo)2 

Ferrous  chloride  

FeCl2 

I9t 

Ferrous  sulphate  

FeSO4  .  7  HaO 

278 

Fluoride  of  chrome 

Cr2F6    8  H2O 

162 

Glaubersalt  .    .                        

Na.2SO4  .  10  H2O 

•722 

Glycerin  
Hydrate  of  alumina  
Hydrochloric  acid  
Hydrofluoric  acid 

C3H5(OH)3 
A12(OH)6 
HC1 
HF 

92 

54i 

36 

20 

Hyposulphite  of  soda                  .        .... 

Na«S,O,  .  *  H.O 

24.8 

Lactic  acid  
Magnesium  chloride  
Manganese  chloride  
Nitrate  of  chrome 

C3H603 
MgCl^HjO 
MnCl^HjO 
CrofNO  V 

90 
203 
198 
476 

Nitrate  of  lead 

PbCNO,), 

771 

Nitric  acid                    

HNOg 

6t 

Oxalate  of  ammonia  

(NH,),C,O,  .  H»O 

142 

Oxalate  of  antimony  

Sb(C2O4K)3  .  6  H2O 

610 

Oxalic  acid 

C2O4H2    2  HjO 

126 

Oxide  of  lead                            ... 

PbO 

227 

Paranitraniline           

C.H.(NOa)NH. 

1-28 

Permanganate  of  potash  
Peroxide  of  hydrogen 

KMn04 
HoO, 

lp 

Phenol 

C  H  OH 

Q4. 

Phosphate  of  soda 

Na-jHPO      I2H2O 

•7C4 

Potash                                     .... 

KjCOg    2  HjO 

Potassium  oxalate              

KHC2O4 

128 

Red  prussiate  .        

K^e-CCN),- 

6<CQ 

Resorcine        .        

C.H.COH), 

no 

Silicate  of  soda     

Na2Si4O9 

704 

Sugar  of  lead  

Pb(C2HqO2)»  .  7  H.O 

770 

Sulphate  of  alumina 

A12(SO4)3    i8H2O 

667 

Sulphate  of  cadmium 

CdSO4  .  2  H2O 

244 

Sulphate  of  copper.  .        

CuSO4  .  5  H2O 

2<O 

Sulphate  of  lead  

PbSO4    ' 

^02 

Sulphate  of  magnesium  

MgSO4  .  7  H.,0 

247 

Sulphate  of  nickel  

NiSO4  .  7  HoO 

281 

Sulphate  of  zinc 

ZnSO4    7  HaO 

288 

Sulphocyanide  of  ammonia    

NH4SCN 

76 

Sulphocyanide  of  copper  
Sulphocyanide  of  iron  

Cu(SCN), 
Fe(SCN), 

180 
172 

Sulphocyanide  of  potash  

KSCN 

97 

Sulphuric  acid  (Oil  of  vitriol) 

H,SO 

98 

\*> 

APPENDIX. 


349 


TABLE    OP    FORMULA    AND    MOLECULAR    WEIGHTS    OF    PRINCIPAL 
CHEMICALS    USED    IN    DYEING. —Continued. 


Name. 

Formula. 

Mol.  wt. 

Sulphurous  acid  

so. 

64 

Soda  calcined  (soda  ash)  

Na-jCOg 

106 

Soda  crystallized 

Na-jCOg  .  10  HaO 

286 

Sodium  aluminate 

Na«ALO« 

280 

Sodium,  bisulphite 

NaHSO3 

104. 

Sodium  hydrosulphite  crystallized  

Na2S2O4  .  2  H2O 

104- 

Sodium  nitrite  

NaNO2 

60 

Sodium  peroxide  

Na,O2 

78 

Sodium  sulphide  crystallized  

NcioS  .  Q  ILO 

24O 

Stannate  of  soda  

Na-jSnOg 

21^ 

Stannic  hydrate 

SnO(OH)2 

160 

Stannous  hydrate 

Sn(OH)2 

I  C  -7 

Tannin          .                                

C14H10O9 

•222 

Tartar            

KH  (C4H4O6) 

1  88 

Tartar  emetic  

K(SbO)C.H,O«  .  *  H,O 

T.12 

Tartar  substitute  

NaHSO4 

I2O 

Tartaric  acid  

C.H«O« 

I<O 

Thiosulphate  of  soda  

NaoS,O,  .  5  H,O 

248 

Tin  chloride  

SnCl4 

260 

Tin  salt 

SnCl2    2  HjO 

22< 

Tungstate  of  soda 

Na2WO4    2  H2O 

•7-5Q 

Water    .            .        ...            ... 

HjO 

oo1-* 
18 

Yellow  prussiate  

K.FefCN^  .  ^  HoO 

427 

Zinc  chloride  

ZnCl2 

4    J 

ia6 

INDEX 


PAGE 

Absorbent  cotton,  preparation  of 41,51 

Absorbent  quality  of  cotton,  testing 41 

Acetic  acid,  action  of,  on  cotton 8 

table  showing  strength  of  solutions  of • 332 

use  of,  in  bleaching 42,  52 

use  of,  in  dyeing  acid  colors 86 

use  of,  in  dyeing  silk 89 

Acid,  amount  of,  in  dyeing  acid  colors 70 

testing  for,  in  bleached  cotton 40 

Acid  and  basic  dyestuffs,  to  distinguish  between 272 

Acid  colors,  function  of  chemicals  used  in  dyeing  of 73 

Acid  dyes 60 

action  of 56 

after-treatment  with  chrome 85 

application  of 69 

application  of,  to  cotton 87 

application  of,  to  silk 88 

applied  in  neutral  bath 70 

classification  of 74 

derivation  of 58 

general  characteristics  of 75 

list  of  principal 90 

on  cotton,  representative 98 

on  silk,  representative 99 

on  wool,  representative 98 

properties  of 58 

theory  of  dyeing 63 

Acid  treatment  in  cotton  bleaching 48 

Acidified  wool,  dyeing  acid  colors  on 85 

Acids,  action  of,  on  wool  and  cotton 5,  7 

testing  fastness  to 297 

After-chromed  dyes 60 

After-mordanting  with  chrome 185 

Algol  dyes 259 

Alizarin 223 

reactions  of 224 

Alkali,  testing  fastness  to 297 


352                                                       INDEX.  * 

PAGE 

Alkali  Blue,  method  of  dyeing 71 

Alkalies,  action  of,  on  wool  and  cotton 6,  8 

Alsatian  madder 225 

Alum,  reaction  of  dyestuffs  with .283 

Ammonia,  reaction  of  dyestuffs  with 282 

Ammoniacal  cochineal ' 234 

Ammonium  acetate,  use  of,  in  dyeing  substantive  colors 161 

Analysis  of  textile  fabrics 310 

Anti-chlor,  use  of,  in  bleaching 40,  51 

Antimonine 131 

Antimony  oxalate 130 

Antimony  salt 130 

Apparatus  for  dyeing 102 

for  dyeing  yarn 171 

for  dye-tests i 

Archil 219,  226 

reactions  of 227 

Autogene  black 204 

Avignon  madder 225 

Bark  extract 228 

Basic  dyes 60 

action  of 56 

after-treatment  of,  with  tannin 120 

application  of 1 18 

application  of,  in  one  bath 127 

application  to  cotton 124 

application  to  silk 119 

derivation  of 58 

effect  of  hard  water  on 118 

list  of  the  principal 142 

on  cotton,  representative 135 

on  silk,  representative 136 

properties  of 58 

theory  of  dyeing 64 

Beaume  hydrometer 325 

Berlin  blue 247 

Bistre 244 

Black  cochineal 233 

Blanket  yarns,  fastness  required  of  colors  on 304 

Bleach  assistants,  composition  of 46 

Bleaching,  testing  fastness  to 300 

Bleaching  cotton 40 

causes  of  tendering  in. 50 

loss  in 50 

Bleaching  powder 44,  46 


INDEX.  353 

PAGE 

Bleaching  powder,  action  of,  on  wool 9 

action  of,  on  wool  and  cotton 7 

reaction  of  dyestuffs  with 284 

table  showing  strengths  of  solutions  of 335 

Bleaching  wool 28,  30 

cost  of 37 

Blue  mordant 88 

Blue  spirits 248 

Boiled-off  liquor 14 

use  of 24,  89 

Boiling-off  silk 14 

Boiling-out  cotton 21,  45 

materials  used  in 22 

Bone-dry  fibre 315 

Bookbinders'  cloth,  fastness  required  of  colors  on 306 

Calculations  used  in  dying 72,  336 

Campeachy  wood 212 

Capillary  speed  of  dyestuffs,  determination  of 278 

Carbonized  rags,  fastness  required  of  colors  on 301 

Carbonizing,  testing  fastness  to no,  297 

Carmine  lake 235 

Carminic  acid 233 

Carpet  yarns,  fastness  required  of  colors  on 304 

scouring  of 18 

Catechin 229 

Catechu 228 

Catechuic  acid 230 

Catechu-tannic  acid 229 

Caustic  soda,  table  showing  strengths  of  solutions  of 333 

Chemic 47 

Chemical  reactions  of  dyestuffs 281 

Chemical  theory  of  dyeing 61 

China  clay  in  fabrics , 319 

Chloride  of  lime 44 

bleaching  cotton  with 40 

Chlorides  on  fabrics,  detection  of 318 

Chlorinated  wool 7,  9 

Chlorine,  action  of,  on  cotton 10 

testing  fastness  to 300 

testing  for,  in  bleached  cotton 40 

Chloring,  testing  fastness  to in 

Chlorogenin 223 

Chlorozone,  use  of,  in  bleaching 43 

Cholesterol 15 

Chrome  green 246 


354  INDEX. 

PAGE 

Chrome  orange 241 

yellow 239 

Chromium  fluoride,  use  of,  with  substantive  dyes 163 

Chromotrop  dyes 86 

Ciba  dyes 259,  262 

Circular  tank,  to  find  capacity  of 77 

Coal-tar  dyes,  comparison  of,  with  vegetable  dyes 59 

Cochineal 220,  233 

carmine 235 

colors  with  different  mordants 234 

reactions  of 233 

Color-lake 62 

Common  equivalents  in  measuring 327 

Common-salt,  detection  of,  in  dyestuffs 274 

table  showing  strengths  of  solutions  of 334 

Comparison  between  degrees  Beaume  and  Twaddle 326 

Conditioning  of  textile  materials 315 

Copperas  vat 256 

Cotton,  action  of  acid  on 5 

action  of  alkalies  on 6 

action  of  bleaching  powder  on 7 

action  of  metallic  salts  on 6 

and  linen,  to  distinguish  between 312 

bleaching  of 40 

bleaching,  operations  in 45 

boiling-out  of 21 

dyeings,  testing  fastness  of 299 

general  method  of  bleaching 44 

hosiery,  fastness  required  of  colors  on 306 

impurities  in  raw 21 

linings,  fastness  required  of  colors  on 306 

piece  goods,  fastness  required  of  colors  on 306 

scouring  with  caustic  soda 13 

scouring  with  soda  ash 13 

scouring  with  soap 14 

slubbing,  fastness  required  of  colors  on 305 

warps,  fastness  required  of  colors  on 305 

wax 21 

wetting-out  of 21 

Coupled  dyes 61 

Crocking,  testing  fastness  to in 

Crop  madder 225 

Cross-dyeing,  testing  fastness  to no,  299 

Cuba  wood 220 

Cudbear 227 

Cutch.. 219,228 


INDEX.  355 

PAGE 

Degumming  silk 14 

Developed  black  on  cotton 196 

on  silk 197 

Developed  dyes 60 

list  of  the  prinicipal 199 

method  of  application 194 

on  cotton 197 

Developing  bath,  preparation  of 199 

Dextrin  in  dyestuffs,  detection  of 278 

on  fabrics,  detection  of 317 

Diazo  body,  action  of  heat  on 195 

Diazo  groups  in  dyes 195 

Diazotized  colors 194 

Diazotizing,  precautions  to  be  taken  in 195 

Diazotizing  bath,  preparation  of 198 

Dichroic  property  of  a  dyestuff,  to  show  the 288 

Dichroism  in  the  compounding  of  shades,  effect  of 289 

Divi-divi 129 

Double  antimony  fluoride , 130 

Dress  goods,  fastness  required  of  colors  on 304 

Dutch  madder • 225 

Dye-baths,  method  of  preparing 72 

Dyes,  classification  of 56,  58,  59 

Dyestuff  manufacturers,  abbreviations  for  designating 99 

Dyestuffs,  adulterations  in.  . 273 

dissolving  of 100 

nomenclature  of '.'. 100 

storage  of 100 

testing  money-value  of 265 

to  determine  classification  of 269 

Ecru  silk 23 

Emulsion,  meaning  of 17 

Emulsion  process,  scouring  raw  wool  by 12 

Epsom  salts  in  dyestuffs,  detection  of   277 

Erythrin 226 

Evernic  acid 226 

Exhaust  test  for  dyestuffs 267 

Exhaustion  of  dye-bath 70,  286 

of  mordant  bath,  to  determine  the  degree  of 288 

Experimental  dye-bath 2 

Factors  influencing  dyeing  process 62 

Fancy  yarns,  fastness  required  of  colors  on 304 

Fankhausine 14,  22 

Fastness  of  colors,  testing 108,  292 

Fermentation  vat 256 


356  INDEX. 

PAGE 

Ferric  chloride,  reaction  of  dyestuffs  with 283 

Fibres,  chemical  study  of  the 5 

Fibroin 23 

Finishing  blue  spirits 249 

Flannels,  fastness  required  of  colors  on 305 

Flannel  yarns,  fastness  required  of  colors  on 304 

Flavine 228 

Fleurs  de  garance 225 

Flowers  of  madder 225 

Formic  acid,  action  of,  on  cotton 8 

French  purple 227 

Fulling,  testing  fastness  to 109,  295 

Full  shade,  amount  of  dyestuff  necessary  for  a 286 

Fustic 218,  220 

analysis  of 222 

reactions  of 222 

Gallo-tannic  acid 128 

Gall-nuts 128 

Galls 129 

Gambier 229 

Garanceux 225 

Garancin 224 

Gelatin  on  fabrics,  detection  of 318 

Glaubersalt 75 

in  dyestuffs,  detection  of 276 

influence  of,  in  dyeing 64,  69,  74 

table  showing  strength  of  solutions  of 334 

Glucose  on  fabrics,  detection  of 318 

Gray  sour 46 

Gum  kino 229 

Gums  on  fabrics,  detection  of 317 

Gypsum  in  fabrics .  319 

Haematoxylon 212 

Hardness  of  water,  methods  of  correcting 20 

Hard  water,  definition  of 20 

Hats,  fastness  required  of  colors  on 305 

Hematin 213 

Hosiery  yarns,  fastness  required  of  colors  on 304 

Hot  pressing,  testing  fastness  to 298 

Hydrated  cellulose 8 

Hydrochloric  acid,  reaction  of  dyestuff  with 282 

table  showing  strengths  of  solutions  of 332 

Hydrometers 325 

Hydrosulphite  powder 254 

Hypochlorous  acid 47 


INDEX.  357 

PAGE 

Ice  colors IQ5 

Indanthrene  dyes 257,  262 

Indican 260 

Indigo 260 

blue 254 

brown 260 

dyeing  with  hydrosulphite  vat 255 

gluten 260 

red 260 

solution,  preparation  of 254 

white 254 

Indigotin 260 

Indirubin 260 

Irish  moss  on  fabrics,  detection  of 318 

Iron  buff 242 

gray 243 

in  water,  influence  of,  in  scouring 21 

Ironing,  testing  fastness  to 298 

Janus  dyes 127 

Japonic  acid 230 

Khaki  color 246 

Kino 229 

Klauder-Weldon  dyeing  machine 172 

Knitting  yarns,  fastness  required  of  colors  on 304 

Lecanoric  acid 226 

Level  dyeing,  precautions  necessary  to  obtain 76 

Light,  standards  for  fastness  to 293 

testing  fastness  to 108,  292 

Lime  boil,  use  of,  in  bleaching 42 

Logwood,  dyeing  on  an  iron  mordant 211 

dyeing  silk  with 212 

dyeing  without  tannin 212 

effect  of  overchroming 210 

in  dyeing 210 

shading  of,  with  yellow 210 

Loose  cotton,  bleaching  of 41,  51 

fastness  required  of  colors  on 305 

Loose  wool,  fastness  required  of  colors  on 301 

Lyons  black  on  silk 233 

Machromin 221 

Maclurin 221 

Madder 218,  223 

colors  with  different  mordants 225 

Magnesium  compounds  on  fabrics,  detection  of 318 


358  INDEX. 

PAGE 

Manganese  brown , , 244 

Mauve,  discovery  of 59 

Mechanical  theory  of  dyeing 62 

Mercerizing,  testing  fastness  to 300 

Metallic  salts,  action  of,  on  wool  and  cotton 6,  9 

Milling,  testing  fastness  to 109 

Mimotannic  acid 230 

Mineral  dyestuffs 59,  61,  239 

matter  in  fabrics,  estimation  of 317 

oil  in  fabrics,  detection  of 316 

Mixed  dyestuffs,  testing  for 268 

Monopol  oil 22 

Mordant  dyes 60 

action  of 57 

derivation  of 58 

effect  of  iron  salts  in  dyeing 183 

general  method  of  dyeing 183 

list  of  principal 189 

properties  of 58 

Mordant  to  use,  to  determine  the  correct  amount  of 287 

Mordanting 9 

Mordanting  cotton,  substances  used  in 127 

with  tannin 137 

Mordanting  wool 186 

Mordants,  comparison  of  different 184 

on  cotton  fabrics,  determination  of 321 

on  woolen  fabrics,  determination  of 319 

salts  of  metals  used  as 65 

use  of 65 

Morin 221 

Morintannic  acid 221 

Mulle  madder 225 

Mungo,  fastness  required  of  colors  on 301 

Muriate  of  tin 248 

Myrobolans 129 

Nanking  cotton 242 

Naphthol  dyes 60 

Natural  dyes,  general  use  of 214 

the  minor 218 

Natural  fur,  dyeing  imitation  of 245 

Nature  of  sizing  on  fabrics,  determination  of 317 

Nitric  acid,  reaction  of  dyestuffs  with 282 

Oil  and  grease  in  fabrics,  estimation  of ' 316 

Oils  used  in  spinning 18 

Old  fustic -. , 223 


INDEX.  359 

PAGE 

Orchil 227 

Organic  acids,  action  of,  on  cotton 6 

Oxalic  acid,  action  of,  on  cotton 8 

Oxidized  dyes 61 

Oxycellulose,  testing  for,  in  bleached  cotton 50 

Oxychlorine 52 

Patent  bark 228 

salt 130 

Pearl  ash 12 

Pectin  substances  in  cotton 21,  46 

Permanent  hardness  of  water 20 

Persis 227 

Perspiration,  testing  fastness  to 109,  297 

Phloroglucin 221 

Phthalein  dyes 87 

Piece  goods  of  wool,  fastness  required  of  colors  on 304 

Pigment  colors,  the  minor 251 

Pigment  dyes 66 

action  of 57 

Pink,  production  of,  with  indanthrene  dyes 258 

Plushes,  fastness  required  of  colors  on 305 

Potash,  use  of,  in  scouring  wool   12 

Potassium  bichromate,  reaction  of  dyestuffs  with 283 

Potassium  permanganate,  bleaching  wool  with 30,  36 

Primuline 194 

on  silk^ 196 

Prussian  blue 246 

Pseudo-purpurin 223 

Purpurin 223 

Quercetin • 228 

Quercitrin 228 

Quercitron 219,  228 

Raw  silk,  coloring-matter  in 23 

impurities  in 22 

Raw  wool,  impurities  in 15 

Rectangular  tank,  to  find  capacity  of 76 

Regain  in  conditioning 315 

Resin  in  fabrics,  detection  of 318 

Resin  soap,  use  of,  in  bleaching   46 

Rosin  oil  in  fabrics,  detection  of 317 

Royal  blue  spirits 248 

Rubbing,  testing  fastness  to ; in,  295 

Rubinic  acid 230 

Rufimoric  acid 221 

Rug  yarns,  fastness  required  of  colors  on 304 


360  INDEX. 

PAGE 

Scouring  cotton  with  caustic  soda 13 

with  soap 14 

with  soda  ash 13 

Scouring  raw  silk 14 

Scouring  wool,  chemicals  used  in 16 

effect  of  excessive  alkali  in 12 

effect  of  high  temperature  in 12 

emulsion  process 16 

proper  temperature  for „• 16 

use  of  alkali  in 17 

use  of  emulsion  process  in 12 

use  of  potash  in 12 

Sericin 14,  23 

Sewing  cotton,  fastness  required  of  colors  on 306 

Shoddy,  fastness  required  of  colors  on 301 

Shrinkage  of  wool  in  scouring 12 

Silicate  of  soda,  use  of,  in  bleaching 46 

Silk  and  cotton  fabric,  analysis  of 310 

Silk,  boiling-off  of 23 

glue 23 

lustring  of 24 

scouring  of  raw : 14 

Silver  cochineal 233 

Sizing  materials  in  a  fabric,  estimation  of 315 

Stubbing,  fastness  required  of  colors  on 304 

Soap,  definition  of 19 

Soaps,  distinction  between  hard  and  soft 19 

for  scouring  wool 19 

suitable  for  use  in  scouring 19 

used  for  boiling-off  silk 24 

Soda  ash  in  dyestuffs,  detection  of 277 

table  showing  strengths  of  solutions  of 333 

Sodium  bisulphite,  bleaching  wool  with 28,  30 

carbonate,  reaction  of  dyestuffs  with 282 

chloride,  detection  of,  in  dyestuffs - 274 

hydrate,  reaction  of  dyestuffs  with 282 

hydrosulphite,  preparation  of 254 

hypochlorite,  preparation  of 43,  52 

use  of,  in  bleaching 43,  52 

peroxide,  bleaching  wool  with 29,  34 

method  of  dissolving 33 

stannate,  use  of,  as  a  mordant 88 

sulphate  in  dyestuffs,  detection  of 276 

Softening  bleached  cotton  .  . 41 

Solid  solution 62 

Solubility  tests  for  dyestuffs 281 


INDEX.  36l 

PAGE 

Solutions  used  for  experimental  dye-bath i 

Solvine 22 

Soupling  silk 23 

Souring  in  bleaching 48 

Stannous  chloride,  reaction  of  dyestuffs  with 283 

Starch  in  dyestuffs,  detection  of 278 

on  fabrics,  detection  of 317 

Steaming,  testing  fastness  to 298 

Stoving,  testing  fastness  to no,  298 

Street  dust,  testing  fastness  to 298 

Stripping  silk 14 

Substantive  dyes   60,  153 

action  of 56 

after-treatment  of,  with  bluestone 151 

after-treatment  of,  with  chrome 151 

application  of,  in  cold  bath 151 

application  of,  to  cotton 149 

application  of,  to  silk 164 

application  of,  to  wool 161 

derivation  of 58 

influence  of  salt  in  dyeing 150 

list  of  principal 174 

on  cotton,  representative 170 

properties  of 58 

shading  of,  with  basic  dyes 152 

use  of  soap  in  dyeing 150 

use  of  soda  ash  in  dyeing 150 

Sugar  in  dyestuffs,  detection  of 278 

Sugar  on  fabrics,  detection  of 318 

Suint 15 

Sulphates  in  fabrics,  detection  of 318 

Sulphur  dyes 61 

after-treatment  of,  with  chrome 203 

list  of  the  principal 206 

method  of  application 203 

method  of  dissolving 205 

obtaining  black  with 203 

on  cotton 203 

use  of 204 

Sulphuric  acid,  reaction  of  dyestuffs  with 281 

table  of  strengths  of  solutions  of 331 

-Sulphurous  acid,  action  on  coloring-matters 33 

Sulphurous  acid  gas,  bleaching  wool  with 28 

Sumac 128 

use  of,  in  dyeing  basic  colors .* 126 

Synthetic  indigo 261 


362  INDEX. 

PAGE 

Tables  for  calculations  in  dyeing 336 

Talc  in  fabrics 319 

Tannic  acid 1 28 

table  showing  strengths  of  solutions  of 334 

Tannin,  fixation  of,  with  copperas 126 

fixation  of,  with  tartar  emetic 125 

Tannin  reagent , 273 

reaction  of  dyestuffs  with 283 

Tannins 127 

Tapestry  yarns,  fastness  required  of  colors  on 304 

Tartaric  acid,  action  of,  oji  cotton 8 

Tartar  emetic ,. 130 

Temporary  hardness  of  water 20 

Thermometry 330 

Theory  of  dyeing 61 

Thio-indigo  dyes 257,  261 

Tinting,  bleaching  wool  and  cotton  by 28 

Tinting  bleached  cotton 41 

dyestuffs  used  for 50 

Tops,  fastness  required  of  colors  on 304 

True  silk  and  artificial  silk,  distinction  between 311 

True  silk  and  tussah  silk,  to  distinguish  between 313 

Turkish  madder 225 

Twaddle  hydrometer 325 

Union  material,  application  of  substantive  dyes  to 162 

Upholstery  yarns,  fastness  required  of  colors  on 305 

Useful  data  in  dyeing 76,  325 

Vat  dyes 61,  254 

classes  of 259 

Vegetable  dyes 59 

Velvets,  fastness  required  of  colors  on 305 

Washing,  testing  fastness  to 108,  293 

Water,  relation  of,  to  wool  scouring 20 

testing  fastness  to 109,  296 

Water  in  dyeing,  influence  of 102 

Weather,  testing  fastness  to 296 

Weaving  yarns,  fastness  required  of  colors  on 304 

Wetting-out  of  cotton 21 

Woaded  black 214 

Wool,  action  of  acid  on 5 

action  of  alkalies  on 6 

action  of  bleaching  powder  on 7 

action  of  metallic  salts  on  .  .                                                           6 


INDEX.  363 

PAGE 

Wool  and  cotton  fabric,  analysis  of 310 

and  silk  fabric,  analysis  of 311 

bleaching  of 28 

dyeings,  testing  fastness  of 292 

fat 15 

silk,  and  cotton  fabric,  analysis  of 311 

Woolen  felt,  fastness  required  of  colors  on 305 

yarn  containing  iron,  scouring  of 13 

scouring  of 13,  17 

Worsted  braids,  fastness  required  of  colors  on 304 

yarns,  scouring  of 18 

Xanthin 223 

Yarns  containing  iron,  scouring  of 19 

Yellow  wood 220 

Young  fustic 223 

Zinc  compounds  on  fabrics,  detection  of 318 

Zinc  dust,  reaction  of  dyestuffs  with 284 

and  acetic  acid,  reaction  of  dyestuffs  with 284 

Zinc  vat 256 


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50 
25 

25 
50 
50 

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CIVIL  ENGINEERING. 

BRIDGES  AND  ROOFS.     HYDRAULICS.     MATERIALS   OF    ENGINEER- 
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*  Burr's  Ancient  and  Modern  Engineering  and  the  Isthmian  Canal 8vo,  3  50 

Comstock's  Field  Astronomy  for  Engineers 8vo,  50 

*  Corthell's  Allowable  Pressures  on  Deep  Foundations I2mo,  25 

CrandalFs  Text-book  on  Geodesy  and  Least  Squares 8vo,  oo 

Davis's  Elevation  and  Stadia  Tables 8vo,  oo 

Elliott's  Engineering  for  Land  Drainage i2mo,  50 

Practical  Farm  Drainage i2mo,  oo 

*Fiebeger's  Treatise  on  Civil  Engineering 8vo,  5  oo 

Flemer's  Phototopographic  Methods  and  Instruments 8vo,  5  oo 

Folwell's  Sewerage.     (Designing  and  Maintenance.) 8vo,  3  oo 

Freitag's  Architectural  Engineering 8vo,  3  50 

French  and  Ives's  Stereotomy 8vo,  2  50 

Goodhue's  Municipal  Improvements 12010,  i  50 

Gore's  Elements  of  Geodesy 8vo,  2  50 

*  Hauch  and  Rice's  Tables  of  Quantities  for  Preliminary  Estimates I2mo,  i  25 

Hayford's  Text-book  of  Geodetic  Astronomy 8vo,  3  oo 

Bering's  Ready  Reference  Tables  (Conversion  Factors) i6mo,  mor.  2  50 

Howe's  Retaining  Walls  for  Earth i2mo,  i  25 

6 


*  Ives's  Adjustments  of  the  Engineer's  Transit  and  Level i6mo,  Bds.  25 

Ives  and  Hilts's  Problems  in  Surveying i6mo,  mor.  i  50 

Johnson's  (J.  B.)  Theory  and  Practice  of  Surveying Small  8vo,  4  oo 

Johnson's  (L.  J.)  Statics  by  Algebraic  and  Graphic  Methods 8vo,  2  oo 

Kinnicutt,  Winslow  and  Pratt's  Purification  of  Sewage.     (In  Preparation). 
Laplace's    Philosophical    Essay    on    Probabilities.       (Truscott    and   Emory.) 

1 2 mo,  2  oo 

Mahan's  Descriptive  Geometry 8vo,  i  50 

Treatise  on  Civil  Engineering.     (1873.)     (Wood.) 8vo,  5  oo 

Merriman's  Elements  of  Precise  Surveying  and  Geodesy 8vo,  2  50 

Merriman  and  Brooks's  Handbook  for  Surveyors i6mo,  mor.  2  oo 

Morrison's  Elements  of  Highway  Engineering.       (In  Press.) 

Nugent's  Plane  Surveying 8vo,  3  50 

Ogden's  Sewer  Design i2mo,  2  oo 

Parsons's  Disposal  of  Municipal  Refuse 8vo,  2  oo 

Patton's  Treatise  on  Civil  Engineering 8vo,  half  leather,  7  50 

Reed's  Topographical  Drawing  and  Sketching 4to,  5  oo 

Rideal's  Sewage  and  the  Bacterial  Purification  of  Sewage 8vo,  4  oo 

Riemer's  Shaft-sinking  under  Difficult  Conditions.     (Corning  and  Peele.).  .8 vo,  3  oo 

Siebert  and  Biggin's  Modern  Stone-cutting  and  Masonry 8vo,  I  50 

Smith's  Manual  of  Topographical  Drawing.     (McMillan.) 8vo,  2  50 

Soper's  Air  and  Ventilation  of  Subways.     (In  Press.) 

Tracy's  Plane  Surveying I6mo,  mor.  3  oo 

*  Trautwine's  Civil  Engineer's  Pocket-book i6mo,  mor.  5  oo 

Venable's  Garbage  Crematories  in  America 8vo,  2  oo 

Methods  and  Devices  for  Bacterial  Treatment  of  Sewage 8vo,  3  oo 

Wait's  Engineering  and  Architectural  Jurisprudence 8vo,  6  oo 

Sheep,  6  50 

Law  of  Contracts 8vo,  3  oo 

Law  of  Operations  Preliminary  to  Construction  in  Engineering  and  Archi- 
tecture  8vo,  s  oo 

Sheep,  5  50 

Warren's  Stereotomy — Problems  in  Stone-cutting 8vo,  2  50 

*  Waterbury's  Vest-Pocket  Hand-book   of    Mathematics   for   Engineers. 

2 JXsf  inches,  mor.  i  oo 
Webb's  Problems  in  the  Use  and  Adjustment  of  Engineering  Instruments. 

i6mo,  mor.  i  25 

Wilson's  Topographic  Surveying 8vo,  3  50 

BRIDGES  AND  ROOFS. 

Boiler's  Practical  Treatise  on  the  Construction  of  Iron  Highway  Bridges.  .8vo,  2  oo 

Burr  and  Falk's  Design  and  Construction  of  Metallic  Bridges 8vo,  5  oo 

Influence  Lines  for  Bridge  and  Roof  Computations 8vo,  3  oo 

Du  Bois's  Mechanics  of  Engineering.     Vol.  II Small  4to,  10  oo 

Foster's  Treatise  on  Wooden  Trestle  Bridges 4to,  5  oo 

Fowler's  Ordinary  Foundations 8vo,  3  50 

French  and  Ives's  Stereotomy 8vo,  2  50 

Greene's  Arches  in  Wood,  Iron,  and  Stone 8vo,  2  50 

Bridge  Trusses 8vo,  2  50 

Roof  Trusses.  „ 8vo,  i  25 

Grimm's  Secondary  Stresses  in  Bridge  Trusses 8vo,  2  50 

Heller's  Stresses  in  Structures  and  the  Accompanyin    Deformations 8vo, 

Howe's  Design  of  Simple  Roof- trusses  in  Wood  and  Steel 8vo,  2  oo 

Symmetrical  Masonry  Arches ^ 8vo,  2  50 

Treatise  on  Arches.  . . 8vo,  4  oo 

Johnson,  Bryan,  and  Turneaure's  Theory  and  Practice  in  the  Designing  of 

Modern  Framed  Structures Small  4to,  10  oo 

7 


Merriman  and  Jacoby's  Text-book  on  Roofs  and  Bridges : 

Part  I.      Stresses  in  Simple  Trusses 8vo,  2  50 

Part  II.    Graphic  Statics 8vo,  2  50 

Part  III.  Bridge  Design 8vo,  2  50 

Part  IV.   Higher  Structures 8vo,  2  50 

Morison's  Memphis  Bridge Oblong  4to,  10  oo 

Sondericker's  Graphic  Statics,  with  Applications  to  Trusses,  Beams,  and  Arches. 

8vo,  2  oo 

Waddell's  De  Pontibus,  Pocket-book  for  Bridge  Engineers i6mo,  mor,  2  oo 

*          Specifications  for  Steel  Bridges I2mo,  50 

Waddell  and  Harrington's  Bridge  Engineering.     (In  Preparation.) 

Wright's  Designing  of  Draw-spans.     Two  parts  in  one  volume 8vo,  3  50 


HYDRAULICS. 

Barnes's  Ice  Formation 8vo,  3  oo 

Bazin's  Experiments  upon  the  Contraction  of  the  Liquid  Vein  Issuing  from 

an  Orifice.     (Trautwine.) 8vo,  2  oo 

Bovey's  Treatise  on  Hydraulics 8vo,  5  oo 

Church's  Diagrams  of  Mean  Velocity  of  Water  in  Open  Channels. 

Oblong  4to.  paper,  i  50 

Hydraulic  Motors .8vo,  2  oo 

Mechanics  of  Engineering .8vo,  6  oo 

Coffin's  Graphical  Solution  of  Hydraulic  Problems i6mo,  morocco,  2  50 

Flather's  Dynamometers,  and  the  Measurement  of  Power i2mo,  3  po 

FolwelTs  Water-supply  Engineering 8vo,  4  oo 

Frizell's  Water-power 8vo,  5  oo 

Fuertes's  Water  and  Public  Health I2mo,  i  50 

Water-filtration  Works i2mo,  2  50 

Ganguillet  and  Kutter's  General  Formula  for  the  Uniform  Flow  of  Water  in 

Rivers  and  Other  Channels.     (Hering  and  Trautwine.) 8vo,  4  oo 

Hazen's  Clean  Water  and  How  to  Get  It Large  I2mo,  i  5o 

Filtration  of  Public  Water-supplies 8vo,  3  oo 

Hazlehurst's  Towers  and  Tanks  for  Water- works 8vo,  2  50 

Herschel's  115  Experiments  on  the  Carrying  Capacity  of  Large,  Riveted,  Metal 

Conduits 8vo,  2  oo 

Hoyt  and  Grover's  River  Discharge 8vo,  2  oo 

Hubbard  and  Kiersted's  Water- works  Management  and  Maintenance 8vo,  4  oo 

*  Lyndon's  Development  and  Electrical  Distribution  of  Water  Power.  . .  .8vo,  3  oo 
Mason's  Water-supply.     (Considered  Principally  from  a  Sanitary  Standpoint.) 

8vo,  4  oo 

Merriman's  Treatise  on  Hydraulics 8vo,  5  oo 

*  Michie's  Elements  of  Analytical  Mechanics 8vo,  4  oo 

Molitor's  Hydraulics  of  Rivers,  Weirs  and  Sluices.     (In  Press.) 

Schuyler's  Reservoirs  for  Irrigation,   Water-power,   and   Domestic   Water- 
supply Large  8vo,  5  oo 

*  Thomas  and  Watt's  Improvement  of  Rivers 4to,  6  oo 

Turneaure  and  Russell's  Public  Water-supplies 8vo,  5  oo 

Wegmann's  Design  and  Construction  of  Dams.     5th  Ed.,  enlarged 4to,  6  oo 

Water-supply  of  the  City  of  New  York  from  1658  to  1895 4to,  10  oo 

Whipple's  Value  of  Pure  Water Large  i2mo,  i  oo 

Williams  and  Hazen's  Hydraulic  Tables 8vo,  i  50 

Wilson's  Irrigation  Engineering Small  8vo,  4  oo 

Wolff's  Windmill  as  .a  Prime  Mover 8vo,  3  oo 

Wood's  Elements  of  Analytical  Mechanics ; 8vo,  3  oo 

Turbines • 8vo,  2  50 

8 


MATERIALS  OF  ENGINEERING. 

Baker's  Roads  and  Pavements 8vo,  5  oo 

Treatise  on  Masonry  Construction 8vo,  5  oo 

Birkmire's  Architectural  Iron  and  Steel 8vo,  3  50 

Compound  Riveted  Girders  as  Applied  in  Buildings 8vo,  2  oo 

Black's  United  States  Public  Works Oblong  4to,  5  oo 

Bleininger's  Manufacture  of  Hydraulic  Cement.     (In  Preparation.) 

*  Bovey's  Strength  of  Materials  and  Theory  of  Structures 8vo,  7  50 

Burr's  Elasticity  and  Resistance  of  the  Materials  of  Engineering 8vo,  7  50 

Byrne's  Highway  Construction 8vo,  5  oo 

Inspection  of  the  Materials  and  Workmanship  Employed  in  Construction. 

i6mo,  3  oo 

Church's  Mechanics  of  Engineering 8vo,  6  oo 

Du  Bois's  Mechanics  of  Engineering. 

Vol.    I.  Kinematics,  Statics,  Kinetics Small  4to,  7  50 

Vol.  II.  The  Stresses  in  Framed  Structures,  Strength  of  Materials  and 

Theory  of  Flexures Small  4to,  10  oo 

*Eckel's  Cements,  Limes,  and  Plasters 8vo,  6  oo 

Stone  and  Clay  Products  used  in  Engineering.     (In  Preparation.) 

Fowler's  Ordinary  Foundations 8vo ,  3  50 

Graves's  Forest  Mensuration 8vo,  4  oo 

Green's  Principles  of  American  Forestry I2mo,  i  50 

*  Greene's  Structural  Mechanics 8vo,  2  50 

Holly  and  Ladd's  Analysis  of  Mixed  Paints,  Color  Pigments  and  Varnishes 

Large  izmo,  2  50 

Johnson's  Materials  of  Construction Large  8vo,  6  oo 

Keep's  Cast  Iron 8vo,  2  50 

Kidder's  Architects  and  Builders'  Pocket-book. i6mo,  5  oo 

Lanza's  Applied  Mechanics 8vo,  7  50 

Maire's  Modern  Pigments  and  their  Vehicles i2mo,  2  oo 

Martens's  Handbook  on  Testing  Materials.     (Henning.)     2  vols 8vo,  7  50 

Maurer's  Technical  Mechanics 8vo,  4  oo 

Merrill's  Stones  for  Building  and  Decoration 8vo,  5  oo 

Merriman's  Mechanics  of  Materials 8vo,  5  oo 

*  Strength  of  Materials i2mo,  i  oo 

Metcalf's  Steel.     A  Manual  for  Steel-users i2mo,  2  oo 

Patton's  Practical  Treatise  on  Foundations 8vo,  5  oo 

Rice's  Concrete  Block  Manufacture 8vo,  2  oo 

Richardson's  Modern  Asphalt  Pavements 8vo,  3  oo 

Richey's  Handbook  for  Superintendents  of  Construction i6mo,  mor.,  4  oo 

*  Ries's  Clays:  Their  Occurrence,  Properties,  and  Uses 8vo,  5  oo 

Sabin's  Industrial  and  Artistic  Technology  of  Paints  and  Varnish 8vo,  3  oo 

*Schwarz's  Longleaf  Pine  in  Virgin  Forest i2mo,  i   25 

Snow's  Principal  Species  of  Wood 8vo,  3  So 

Spalding's  Hydraulic  Cement tamo,  2  oo 

Text-book  on  Roads  and  Pavements i2mo,  2  oo 

Taylor  and  Thompson's  Treatise  on  Concrete,  Plain  and  Reinforced 8vo,  5  oo 

Thurston's  Materials  of  Engineering.     In  Three  Parts 8vo,  8  oo 

Part  I.     Non-metallic  Materials  of  Engineering  and  Metallurgy 8vo,  2  oo 

Part  II.     Iron  and  Steel 8vo,  3  50 

Part  III.     A  Treatise  on  Brasses,  Bronzes,  and  Other  Alloys  and  their 

Constituents 8vo,  2  50 

Tillson's  Street  Pavements  and  Paving  Materials 8vo,  4  oo 

Turneaure  and  Maurer's  Principles  of  Reinforced  Concrete  Construction..  .8vo,  3  oo 
Wood's  (De  V.)  Treatise  on  the  Resistance  of  Materials,  and  an  Appendix  on 

the  Preservation  of  Timber 8vo,  2  oo 

Wood's  (M.  P.)  Rustless  Coatings:    Corrosion  and  Electrolysis  of  Iron  and 

Steel 8vo,  4  oo 

9 


RAILWAY  ENGINEERING. 

Andrews's  Handbook  for  Street  Railway  Engineers 3x5  inches,  mor.     i  25 

Berg's  Buildings  and  Structures  of  American  Railroads 4to,    5  oo 


Brooks's  Handbook  of  Street  Railroad  Location i6mo,  mor. 

Butt's  Civil  Engineer's  Field-book i6mo,  mor. 

CrandalTs  Railway  and  Other  Earthwork  Tables 8vo, 

Transition  Curve i6mo,  mor. 


*  Crockett's  Methods  for  Earthwork  Computations 8vo, 

Dawson's  "Engineering"  and  Electric  Traction  Pocket-book i6mo,  mor.  5  oo 

Dredge's  History  of  the  Pennsylvania  Railroad:    (1879) Paper,  5  oo 

Fisher's  Table  of  Cubic  Yards Cardboard,  25 

Godwin's  Railroad  Engineers'  Field-book  and  Explorers'  Guide.  .  .  i6mo,  mor.  2  50 
Hudson's  Tables  for  Calculating  the  Cubic  Contents  of  Excavations  and  Em- 
bankments  8vo,  i  oo 

Ives   and  Hilts's   Problems  in  Surveying,  Railroad   Surveying  and  Geodesy 

i6mo,  mor.  i  50 

Molitor  and  Beard's  Manual  for  Resident  Engineers i6mo,  i  oo 

Wagle's  Field  Manual  for  Railroad  Engineers i6mo,  mor.  3  oo 

Philbrick's  Field  Manual  for  Engineers i6mo,  mor.  3  oo 

Raymond's  Railroad  Engineering.     3  volumes. 

Vol.      I.  Railroad  Field  Geometry.     (In  Preparation.) 

Vol.    II.  Elements  of  Railroad  Engineering 8vo,  3  50 

Vol.  III.  Railroad  Engineer's  Field  Book.     (In  Preparation.) 

Searles's  Field  Engineering i6mo,  mor.  3  oo 

Railroad  Spiral i6mo,  mor.  i  50 

Taylor's  Prismoidal  Formulae  and  Earthwork 8vo,  i  50 

*Trautwine's  Field  Practice  of  Laying   Out  Circular  Curves   for  Railroads. 

i2mo.  mor,  2  50 

*  Method  of  Calculating  the  Cubic  Contents  of  Excavations  and  Embank- 

ments by  the  Aid  of  Diagrams 8vo,  2  oo 

Webb's  Economics  of  Railroad  Construction Large  i2mo,  2  50 

Railroad  Construction . i6mo,  mor.  5  oo 

Wellington's  Economic  Theory  of  the  Location  of  Railways Small  8vo,  5  oo 

DRAWING. 

Barr's  Kinematics  of  Machinery 8vo,  2  50 

*  Bartlett's  Mechanical  Drawing 8vo,  3  oo 

*  "                    "               "             Abridged  Ed 8vo,  i  50 

Coolidge's  Manual  of  Drawing 8vo,  paper,  i  oo 

Coolidge  and  Freeman's  Elements  of  General  Drafting  for  Mechanical  Engi- 
neers  Oblong  4to,  2  50 

Durley's  Kinematics  of  Machines 8vo,  4  oo 

Emch's  Introduction  to  Projective  Geometry  and  its  Applications 8vo,  2  50 

Hill's  Text-book  on  Shades  and  Shadows,  and  Perspective 8vo,  2  oo 

Jamison's  Advanced  Mechanical  Drawing 8vo,  2  oo 

Elements  of  Mechanical  Drawing 8vo,  2  50 

Jones's  Machine  Design: 

Part  I.     Kinematics  of  Machinery 8vo,  i  50 

Part  II.    Form,  Strength,  and  Proportions  of  Parts 8vo,  3  oo 

MacCord's  Elements  of  Descriptive  Geometry 8vo,  3  oc 

Kinematics ;  or,  Practical  Mechanism 8vo,  5  oo 

Mechanical  Drawing 4to,  4  oo 

Velocity  Diagrams 8vo,  i  50 

McLeod's  Descriptive  Geometry Large  i2mo,  i  50 

*  Mahan's  Descriptive  Geometry  and  Stone-cutting 8vo,  i  50 

Industrial  Drawing.     (Thompson.) 8vo,  3  50 

10 


Moyer's  Descriptive  Geometry 8vo,  2  oo 

Reed's  Topographical  Drawing  and  Sketching 4to,  5  oo 

Reid's  Course  in  Mechanical  Drawing 8vo,  2  oo 

Text-book  of  Mechanical  Drawing  and  Elementary  Machine  Design.  8vo,  3  oo 

Robinson's  Principles  of  Mechanism 8vo,  3  oo 

Schwamb  and  Merrill's  Elements  of  Mechanism !8vo,  3  oo 

Smith's  (R.  S.)  Manual  of  Topographical  Drawing.     (McMillan.) 8vo,  2  50 

Smith  (A.  W.)  and  Marx's  Machine  Design 8vo,  3  oo 

*  Titsworth's  Elements  of  Mechanical  Drawing Oblong  8vo,  i  25 

Warren's  Drafting  Instruments  and  Operations i2mo,  i  25 

Elements  of  Descriptive  Geometry,  Shadows,  and  Perspective 8vo,  3  50 

Elements  of  Machine  Construction  and  Drawing 8vo,  7  50 

Elements  of  Plane  and  Solid  Free-hand  Geometrical  Drawing.  .  . .  i  .2mo,  i  oo 

General  Problems  of  Shades  and  Shadows 8vo,  3  oo 

Manual  of  Elementary  Problems  in  the  Linear  Perspective  of  Form  and 

Shadow i2mo,  i  oo 

Manual  of  Elementary  Projection  Drawing i2mo,  i  50 

Plane  Problems  in  Elementary  Geometry i2mo,  i  25 

Problems,  Theorems,  and  Examples  in  Descriptive  Geometry 8vo,  2  50 

Weisbach's    Kinematics    and    Power    of    Transmission.        (Hermann    and 

Klein.) 8vo,  5  oo 

Wilson's  (H.  M.)  Topographic  Surveying 8vo,  3  50 

Wilson's  (V.  T.)  Free-hand  Lettering 8vo,  i  oo 

Free-hand  Perspective 8vo,  2  50 

Woolf*  s  Elementary  Course  in  Descriptive  Geometry Large  8vo,  3  oo 

ELECTRICITY  AND  PHYSICS. 

*  Abegg's  Theory  of  Electrolytic  Dissociation,     (von  Ende.) i2mo,  i  25 

Andrews's  Hand-Book  for  Street  Railway  Engineering 3X5  inches,  mor.,  i  25 

Anthony  and  Brackett's  Text-book  of  Physics.     (Magie.) Large  i2mo,  3  oo 

Anthony's  Lecture-notes  on  the  Theory  of  Electrical  Measurements.  . .  . i2tno,  i  oo 

Benjamin's  History  of  Electricity 8vo,  3  oo 

Voltaic  Cell 8vo,  3  oo 

Betts's  Lead  Refining  and  Electrolysis 8vo,  4  oo 

Classen's  Quantitative  Chemical  Analysis  by  Electrolysis.     (Boltwood.).Svo,  3  oo 

*  Collins's  Manual  of  Wireless  Telegraphy i2mo,  i  50 

Mor.  2  oo 

Crehore  and  Squier's  Polarizing  Photo-chronograph 8vo,  3  oo 

*  Danneel's  Electrochemistry.     (Merriam.) i2mo,  i  25 

Dawson's  "Engineering"  and  Electric  Traction  Pocket-book i6mo,  mor  5  oo 

Dolezalek's  Theory  of  the  Lead  Accumulator  (Storage  Battery),    (von  Ende.) 

i2mo,  2  50 

Duhem's  Thermodynamics  and  Chemistry.     (Burgess.) 8vo,  4  oo 

Flather's  Dynamometers,  and  the  Measurement  of  Power i2mo,  3  oo 

Gilbert's  De  Magnete.     (Mottelay.) 8vo,  2  50 

*  Hanchett's  Alternating  Currents i2mo,  i  oo 

Bering's  Ready  Reference  Tables  (Conversion  Factors) i6mo,  mor.  2  50 

Hobart  and  Ellis's  High-speed  Dynamo  Electric  Machinery.     (In  Press.) 

Holman's  Precision  of  Measurements 8vo,  2  oo 

Telescopic   Mirror-scale  Method,  Adjustments,  and  Tests.  . .  .Large  8vo,  73 

*  Karapetoff 's  Experimental  Electrical  Engineering 8vo,  6  oo 

Kinzbrunner's  Testing  of  Continuous-current  Machines 8vo,  2  oo 

Landauer's  Spectrum  Analysis.     (Tingle.) 8vo,  3  oo 

Le  Chatelier's  High-temperature  Measurements.  (Boudouard — Burgess.)  i2mo,  3  oo 

Lob's  Electrochemistry  of  Organic  Compounds.     (Lorenz.) 8vo,  3  oo 

*  Lyndon's  Development  and  Electrical  Distribntion  of  Water  Power  . . .  .8vo,  3  oo 

*  Lyons's  Treatise  on  Electromagnetic  Phenomena.  Vols.  I.  and  II.  8vo,  each,  6  oo 

*  Michie's  Elements  of  Wave  Motion  Relating  to  Sound  and  Light 8vo,  4  oo 

11 


Morgan's  Outline  of  the  Theory  of  Solution  and  its  Results i2mo,  i  oo 

*  Physical  Chemistry  for  Electrical  Engineers xamo,  i  50 

Niaudet's  Elementary  Treatise  on  Electric  Batteries.     (Fishback).  .  . .  i2mo,  2   50 

*  Morris's  Introduction  to  the  Study   of  Electrical  Engineering 8vo,  2  50 

*  Parshall  and  Hobart's  Electric  Machine  Design 4to,  half  morocco,  12  50 

Reagan's  Locomotives:    Simple,  Compound,  and  Electric.      New  Edition. 

Large  12 mo,  3  50 

*  Rosenberg's  Electrical  Engineering.     (Haldane  Gee — Kinzbrunner.).  .  .8vo,  2  oo 

Ryan,  Norris,  and  Hoxie's  Electrical  Machinery.     Vol.  1 8vo,  2  50 

Swapper's  Laboratory  Guide  for  Students  in  Physical  Chemistry i2mo,  i  oo 

Thurston's  Stationary  Steam-engines 8vo,  2  50 

*  Tillman's  Elementary  Lessons  in  Heat 8vo,  i   50 

Tory  and  Pitcher's  Manual  of  Laboratory  Physics Large  i2mo,  2  oo 

Ulke's  Modern  Electrolytic  Copper  Refining 8vo,  3  oo 

LAW. 

*  Davis's  Elements  of  Law 8vo,  2  50 

*  Treatise  on  the  Military  Law  of  United  States 8vo,  7  oo 

*  Sheep,  7  50 

*  Dudley's  Military  Law  and  the  Procedure  of  Courts-martial  .  .  .  .Large  12 mo,  2  50 

Manual  for  Courts-martial i6mo,  mor.  i  50 

Wait's  Engineering  and  Architectural  Jurisprudence 8vo,  6  oo 

Sheep,  6  50 

Law  of  Contracts 8vo,  3  oo 

Law  of  Operations  Preliminary  to  Construction  in  Engineering  and  Archi- 
tecture  8vo  5  oo 

Sheep,  5  50 
MATHEMATICS. 

Baker's  Elliptic  Functions 8vo,  50 

Briggs's  Elements  of  Plane  Analytic  Geometry.    (Bocher) i2mo,  oo 

*  Buchanan's  Plane  and  Spherical  Trigonometry 8vo,  oo 

Byerley's  Harmonic  Functions 8vo,  oo 

Chandler's  Elements  of  the  Infinitesimal  Calculus 12 mo,  oo 

Compton's  Manual  of  Logarithmic  Computations i2mo,  50 

Davis's  Introduction  to  the  Logic  of  Algebra 8vo,  50 

*  Dickson's  College  Algebra Large  i2mo,  50 

*  Introduction  to  the  Theory  of  Algebraic  Equations Large  12  mo,  25 

Emch's  Introduction  to  Projective  Geometry  and  its  Applications 8vo,  50 

Fiske's  Functions  of  a  Complex  Variable 8vo,  oo 

Halsted's  Elementary  Synthetic  Geometry 8vo,  50 

Elements  of  Geometry 8vo,  75 

*  Rational  Geometry I2mo,  50 

Hyde's  Grassmann's  Space  Analysis 8vo,  oo 

*  Jonnson's  (J    B.)  Three-place  Logarithmic  Tables:  Vest-pocket  size,  paper,  15 

100  copies,  5  oo 

*  Mounted  on  heavy  cardboard,  8X 10  inches,  25 

10  copies,  2  oo 
Johnson's  (W.  W.)  Abridged  Editions  ot  Differential  and  Integral  Calculus 

Large  i2mo,  i  vol.  2  50 

Curve  Tracing  in  Cartesian  Co-ordinates i2mo,  i  oo 

Differential  Equations 8vo,  i  oo 

Elementary  Treatise  on  Differential  Calculus.     (In  Press.) 

Elementary  Treatise  on  the  Integral  Calculus Large  i2mo,  i  50 

*  Theoretical  Mechanics i2mo,  3  oo 

Theory  of  Errors  and  the  Method  of  Least  Squares i2mo,  i  50 

Treatise  on  Differential  Calculus Large  i2mo,  3  oo 

Treatise  on  the  Integral  Calculus Large  i2mo,  3  oo 

Treatise  on  Ordinary  and  Partial  Differential  Equations. . Large  I2mo,  3  50 

12 


Laplace's  Philosophical  Essay  on  Probabilities.     (Truscott  and  Emory.). i2mo,     2  oo 

*  Ludlow  and  Bass's  Elements  of  Trigonometry  and  Logarithmic  and  Other 

Tables 8vo,     3  oo 

Trigonometry  and  Tables  published  separately Each,     2  oo 

*  Ludlow's  Logarithmic  and  Trigonometric  Tables 8vo,     i  oo 

Macfarlane's  Vector  Analysis  and  Quaternions 8vo,     i  oo 

McMahon's  Hyperbolic  Functions 8vo,     i  oo 

Manning's  IrrationalNumbers  and  their  Representation  bySequences  and  Series 

i2mo,     i  25 
Mathematical  Monographs.     Edited  by  Mansfield  Merriman  and  Robert 

S.  Woodward Octavo,  each    i  oo 

No.  i.  History  of  Modern  Mathematics,  by  David  Eugene  Smith. 
No.  2.  Synthetic  Projective  Geometry,  by  George  Bruce  Halsted. 
No.  3.  Determinants,  by  Laenas  Gifford  Weld.  No.  4.  Hyper- 
bolic Functions,  by  James  McMahon.  Ro.  5.  Harmonic  Func- 
tions, by  William  E.  Byerly.  No.  6.  Grassmann's  Space  Analysis, 
by  Edward  W.  Hyde.  No.  7.  Probability  and  Theory  of  Errors, 
by  Robert  S.  Woodward.  No.  8.  Vector  Analysis  and  Quaternions, 
by  Alexander  Macfarlane.  No.  9.  Differential  Equations,  by 
William  Woolsey  Johnson.  No.  10.  The  Solution  of  Equations, 
by  Mansfield  Merriman.  No.  n.  Functions  of  a  Complex  Variable, 
by  Thomas  S.  Fiske. 

Maur er's  Technical  Mechanics 8vo,    4  oo 

Mertfman's  Method  of  Least  Squares 8vo,    2  oo 

Solution  of  Equations 8vo,    i  oo 

Rice  and  Johnson's  Differential  and  Integral  Calculus.     2  vols.  in  one. 

Large  i2mo,     i  50 

Elementary  Treatise  on  the  Differential  Calculus Large  i2mo,     3  oo 

Smith's  History  of  Modern  Mathematics 8vo,    i  oo 

*  Veblen  and  Lennes's  Introduction  to  the  Real  Infinitesimal  Analysis  of  One 

Variable 8vo,   2  oo 

*  Waterbury's  Vest  Pocket  Hand-Book  of  Mathematics  for  Engineers. 

2^  Xsf  inches,  mor,,     i  oo 

Weld's  Determinations 8vo,    I  oo 

Wood's  Elements  of  Co-ordinate  Geometry 8vo,    2  oo 

Woodward's  Probability  and  Theory  of  Errors 8vo,    I  oo 

MECHANICAL  ENGINEERING. 

MATERIALS  OF   ENGINEERING,  STEAM-ENGINES  AND  BOILERS. 

Bacon's  Forge  Practice i2mo,  i  so 

Baldwin's  Steam  Heating  for  Buildings i2mo,  2  50 

Bait's  Kinematics  of  Machinery 8vo,  2  50 

*  Bartlett's  Mechanical  Drawing 8vo,  3  oo 

*  "  "  "        Abridged  Ed 8vo,     150 

Benjamin's  Wrinkles  and  Recipes i2mo,    2  oo 

*  Burr's  Ancient  and  Modern  Engineering  and  the  Isthmian  Canal 8vo,    3  50 

Carpenter's  Experimental  Engineering 8vo,    6  oo 

Heating  and  Ventilating  Buildings 8vo,    4  oo 

Clerk's  Gas  and  Oil  Engine Large  i2mo,    4  oo 

Compton's  First  Lessons  in  Metal  Working i2mo,        50 

Compton  and  De  Groodt's  Speed  Lathe I2mo,        50 

Coolidge's  Manual  of  Drawing 8vo,  paper,        oo 

Coolidge  and  Freeman's  Elements  of  General  Drafting  for  Mechanical  En- 
gineers  Oblong  4to, 

Cromwell's  Treatise  on  Belts  and  Pulleys i2mo, 


Treatise  on  Toothed  Gearing I2mo, 

Durley's  Kinematics  of  Machines 8vo,    4  oo 

13 


Flather's  Dynamometers  and  the  Measurement  of  Power i2mo,  3  oo 

Rope  Driving i2mo,  2  o° 

Gill's  Gas  and  Fuel  Analysis  for  Engineers i2mo,  i  25 

Goss';',  Locomotive  Sparks 8vo,  2  oo 

Hall's  Car  Lubrication i2mo,  i  oo 

Bering's  Ready  Reference  Tables  (Conversion  Factors) i6mo,  mor.,  2  50 

Hobart  and  Eliis's  High  Speed  Dynamo  Electric  Machinery.     (In  Press.) 

Button's  Gas  Engine 8vo,  5  oo 

Jamison's  Advanced  Mechanical  Drawing 8vo,  2  oo 

Elements  of  Mechanical  Drawing 8vo,  2  50 

Jones's  Machine  Design: 

Part  I.     Kinematics  of  Machinery 8vo,  i  50 

Part  II.     Form,  Strength,  and  Proportions  of  Parts 8vo,  3  oo 

Kent's  Mechanical  Engineers'  Pocket-book i6mo,  mor.,  5  oo 

Kerr's  Power  and  Power  Transmission 8vo,  2  oo 

Leonard's  Machine  Shop  Tools  and  Methods', 8vo,  4  oo 

*  Lorenz's  Modern  Refrigerating  Machinery.    (Pope,  Haven,  and  Dean.) .  .  8vo,  4  oo 
MacCord's  Kinematics;  or,  Practical  Mechanism. 8vo,  s  oo 

Mechanical  Drawing 4to,  4  oo 

Velocity  Diagrams 8vo,  i  50 

MacFar land's  Standard  Reduction  Factors  for  Gases 8vo,  i  50 

Mahan's  Industrial  Drawing.     (Thompson.) 8vo,  3  50 

*  Parshall  and  Hobart's  Electric  Machine  Design  .  .  .  .Small  4to,  half  leather,  12  50 
Peele's  Compressed  Air  Plant  for  Mines.     (In  Press.) 

Poole's  Calorific  Power  of  Fuels 8vo,  3  oo 

*  Porter's  Engineering  Reminiscences,  1855  to  1882 8vo,  3  oo 

Reid's  Course  in  Mechanical  Drawing 8vo,    2  oo 

Text-book  of  Mechanical  Drawing  and  Elementary  Machine  Design. 8vo,  3  oo 

Richard's  Compressed  Air i2mo,  i  50 

Robinson's  Principles  of  Mechanism , .  .  8vo,  3  oo 

Schwamb  and  Merrill's  Elements  of  Mechanism 8vo,  3  oo 

Smith's  (O.)  Press-working  of  Metals 8vo,  3  oo 

Smith  (A.  W.)  and  Marx's  Machine  Design 8vo,  3  oo 

Sorel's  Carbureting  and  Combustion  in  Alcohol  Engines.      (Woodward  and 

Preston.) Large  i2mo,  3  oo 

Thurston's  Animal  as  a  Machine  and  Prime  Motor,  and  the  Laws  of  Energetics. 

1 2 mo,  i  oo 

Treatise  on  Friction  and  Lost  Work  in  Machinery  and  Mill  Work...  8vo9  3  oo 

Tillson's  Complete  Automobile  Instructor i6mo,  i  50 

mor.,  2  oo 

*  Titsworth's  Elements  of  Mechanical  Drawing Oblong  8vo,  i  25 

Warren's  Elements  of  Machine  Construction  and  Drawing 8vo,  7  50 

*  Waterbury's  Vest  Pocket  Hand  Book  of  Mathematics  for  Engineers. 

2jX5l  inches,  mor.,  i  oo 
Weisbach's    Kinematics    and    the    Power    of    Transmission.     (Herrmann — 

Klein.) 8vo,  5  oo 

Machinery  of  Transmission  and  Governors.     (Herrmann — Klein.).  .3vo,  5  oo 

Wolff's  Windmill  as  a  Prime  Mover 8vo,  3  oo 

Wood's  Turbines 8vo,  a  50 

MATERIALS  OF  ENGINEERING. 

*  Bovey's  Strength  of  Materials  and  Theory  of  Structures 8vo,  7  50 

Burr's  Elasticity  and  Resistance  of  the  Materials  of  Engineering 8vo,  7  so 

Church's  Mechanics  of  Engineering 8vo,  6  oo 

*  Greene's  Structural  Mechanics 8vo,  2  50 

Holley  and  Ladd's  Analysis  of  Mixed  Paints,  Color  Pigments,  and  Varnishes. 

Large  i2mo,  2  50 

Johnson's  Materials  of  Construction 8vo,  6  oo 

Keep's  Cast  Iron 8vo,  2  50 

Lanza's  Applied  Mechanics 8vo,  7  SO 

14 


Maire's  Modern  Pigments  and  their  Vehicles i2mo,  2  oo 

Martens's  Handbook  on  Testing  Materials.     (Henning.) 8vo,  7  50 

Maurer's  Technical  Mechanics 8vo,  4  oo 

Merriman's  Mechanics  of  Materials 8vo,  5  oo 

*         Strength  of  Materials i2mo,  i  oo 

Metcalf  s  Steel.     A  Manual  for  Steel-users i2mo,  2  oo 

Sabin's  Industrial  and  Artistic  Technology  of  Paints  and  Varnish 8vo,  3  oo 

Smith's  Materials  of  Machines 1 21110,  i  oo 

Thurston's  Materials  of  Engineering 3  vols.,  8vo,  8  oo 

Part  I.     Non-metallic  Materials  of  Engineering,  see  Civil  Engineering, 
page  9. 

Part  II.     Iron  and  Steel 8vo,  3  50 

Part  III.     A  Treatise  on  Brasses,  Bronzes,  and  Other  Alloys  and  their 

Constituents 8vo,  2  50 

Wood's  (De  V.)  Elements  of  Analytical  Mechanics 8vo,  3  oo 

Treatise  on    the    Resistance    of    Materials  and    an  Appendix  on  the 

Preservation  of  Timber 8vo,  2  oo 

Wood's  (M.  P.)  Rustless  Coatings:    Corrosion  and  Electrolysis  of  Iron  and 

Steel 8vo,  4  oo 


STEAM-ENGINES  AND  BOILERS. 

Berry's  Temperature-entropy  Diagram i2mo,  i  25 

Carnot's  Reflections  on  the  Motive  Power  of  Heat.     (Thurston.) izmo,  i  50 

Chase's  Art  of  Pattern  Making i2mo,  2  50 

Creighton's  Steam-engine  and  other  Heat-motors 8vo,    5  oo 

Dawson's  "Engineering"  and  Electric  Traction  Pocket-book. . .  .i6mo,  mor.,  5  oo 

Ford's  Boiler  Making  for  Boiler  Makers i8mo,  i  oo 

Goss's  Locomotive  Performance 8vo,  5  oo 

Hemenway's  Indicator  Practice  and  Steam-engine  Economy i2mo,  2  oo 

Button's  Heat  and  Heat-engines 8vo,  5  oo 

Mechanical  Engineering  of  Power  Plants 8vo,  5  oo 

Kent's  Steam  boiler  Economy 8vo,  4  oo 

Kneass's  Practice  and  Theory  of  the  Injector 8vo,  i  50 

MacCord's  Slide-valves 8vo,  2  oo 

Meyer's  Modern  Locomotive  Construction 4to,  10  oo 

Moyer's  Steam  Turbines.     (Tn  Press.) 

Peabody's  Manual  of  the  Steam-engine  Indicator I2mo.  i  50 

Tables  of  the  Properties  of  Saturated  Steam  and  Other  Vapors 8vo,  i  oo 

Thermodynamics  of  the  Steam-engine  and  Other  Heat-engines 8vo,  5  oo 

Valve-gears  for  Steam-engines 8vo,  2  50 

Peabody  and  Miller's  Steam-boilers 8vo,  4  oo 

Pray's  Twenty  Years  with  the  Indicator Large  8vo,  2  50 

Pupin's  Thermodynamics  of  Reversible  Cycles  in  Gases  and  Saturated  Vapors. 

(Osterberg.) I2mo,  i  25 

Reagan's  Locomotives:    Simple,  Compound,  and  Electric.     New  Edition. 

Large  12 mo,  3  50 

Sinclair's  Locomotive  Engine  Running  and  Management i2mo,  2  oo 

Smart's  Handbook  of  Engineering  Laboratory  Practice i2mo,  2  50 

Snow's  Steam-boiler  Practice 8vo,  3  oo 

Spangler's  Notes  on  Thermodynamics i2mo,  i  oo 

Valve-gears 8vo,  2  50 

Spangler,  Greene,  and  Marshall's  Elements  of  Steam-engineering 8vo,  3  oo 

Thomas's  Steam-turbines 8vo,  4  oo 

Thurston's  Handbook  of  Engine  and  Boiler  Trials,  and  the  Use  of  the  Indi- 
cator and  the  Prony  Brake 8vo,  5  oo 

Handy  Tables 8vo,  i  50 

Manual  of  Steam-boilers,  their  Designs,  Construction,  and  Opfcration..8vo,  5  oo 

15 


Thurston's  Manual  of  the  Steam-engine 2  vols.,  8vo,  10  oo 

Part  I.     History,  Structure,  and  Theory 8vo,  6  oo 

Part  II.     Design,  Construction,  and  Operation 8vo,  6  oo 

Stationary  Steam-engines 8vo,  2  50 

Steam-boiler  Explosions  in  Theory  and  in  Practice 12mo,  i  50 

Wehrenfenning's  Analysis  and  Softening  of  Boiler  Feed-water  (Patterson)   8vo,  4  oo 

Weisbach's  Heat,  Steam,  and  Steam-engines.     (Du  Bois.) 8vo,  5  oo 

Whitham's  Steam-engine  Design 8vo,  5  oo 

Wood's  Thermodynamics,  Heat  Motors,  and  Refrigerating  Machines.  .  .8vo,  4  oo 

MECHANICS  PURE  AND  APPLIED. 

Church's  Mechanics  of  Engineering 8vo,  6  oo 

Notes  and  Examples  in  Mechanics 8vo,  a  oo 

Dana's  Text-book  of  Elementary  Mechanics  for  Colleges  and  Schools .  .  1 2mo,  i  50 
Du  Bois's  Elementary  Principles  of  Mechanics: 

Vol.      I.     Kinematics 8vo,  3  50 

Vol.    II.     Statics 8vo,  4  oo 

Mechanics  of  Engineering.     Vol.    I Small  4to,  7  50 

VoL  II Small  4to,  10  oo 

*  Greene's  Structural  Mechanics 8vo,  2  50 

James's  Kinematics  of  a  Point  and  the  Rational  Mechanics  of  a  Particle. 

Large  12mo,  2  oo 

*  Johnson's  (W.  W.)  Theoretical  Mechanics 12mo,  3  oo 

Lanza's  Applied  Mechanics 8vo,  7  50 

*  Martin's  Text  Book  on  Mechanics,  Vol.  I,  Statics 12mo,  i  25 

*  Vol.  2,  Kinematics  and  Kinetics  .  .I2mo,     l  50 
Maurer's  Technical  Mechanics 8vo,    4  oo 

*  Merriman's  Elements  of  Mechanics 12mo,     i  oo 

Mechanics  of  Materials 8vo,  5  oo 

*  Michie's  Elements  of  Analytical  Mechanics 8vo,  4  oo 

Robinson's  Principles  of  Mechanism 8vo,  3  oo 

Sanborn's  Mechanics  Problems Large  12mo,  i  50 

Schwamb  and  Merrill's  Elements  of  Mechanism 8vo,  3  oo 

Wood's  Elements  of  Analytical  Mechanics 8vo,  3  oo 

Principles  of  Elementary  Mechanics 12mo,    I  25 

MEDICAL. 

Abderhalden's  Physiological  Chemistry  in  Thirty  Lectures.     (Hall  and  Defren). 

(In  Press), 
von  Behring's  Suppression  of  Tuberculosis.     (Bolduan.) 12010,    i  oo 

*  Bolduan's  Immune  Sera 1 2mo,     i  50 

Davenport's  Statistical  Methods  with  Special  Reference  to  Biological  Varia- 
tions   i6mo,  mor.,     i  30 

Ehrlich's  Collected  Studies  on  Immunity.     (Bolduan.) 8vo,  6  oo 

*  Fischer's  Physiology  of  Alimentation Large  i2mo,  cloth,  2  oo 

de  Fursac's  Manual  of  Psychiatry.     (Rosanoff  and  Collins.) Large  i2mo,  2  50 

Hammarsten's  Text-book  on  Physiological  Chemistry.     (Mandel.) 8vo,  4  oo 

Jackson's  Directions  for  Laboratory  Work  in  Physiological  Chemistry . .  ,8vo,  i  25 

Lassar-Cohn's  Practical  Urinary  Analysis.     (Lorenz.) I2mo,  I  oo 

Mandel's  Hand  Book  for  the  Bio-Chemical  Laboratory i2mo,  i  50 

*  Pauli's  Physical  Chemistry  in  the  Service  of  Medicine.     (Fischer.) I2mo,  i  25 

*  Pozzi-Escot's  Toxins  and  Venoms  and  their  Antibodies.     (Cohn.) i2mo,  i  oo 

Rostoski's  Serum  Diagnosis.     (Bolduan.) i2mo,  i  oo 

Ruddiman's  Incompatibilities  in  Prescriptions 8vo,  2  oo 

Whys  in  Pharmacy I2mo,  i  oo 

Salkowski's  Physiological  and  Pathological  Chemistry.     (Orndorff.) 8vo,  2  50 

*  Satterlee's  Outlines  of  Human  Embryology X2mo,  i  25 

Smith's  Lecture  Notes  on  Chemistry  for  Dental  Students 8vo,  2  50 

16 


Steel's  Treatise  on  the  Diseases  of  the  Dog 8vo,  3  50 

*  Whipple's  Typhoid  Fever Large  I2mo,  3  oo 

Woodhull's  Notes  on  Military  Hygiene i6mo,  i  50 

*  Personal  Hygiene 121110,  i  oo 

Worcester  and  Atkinson's  Small  Hospitals  Establishment  and  Maintenance, 

and  Suggestions  for  Hospital  Architecture,  with  Plans  for  a  Small 

Hospital i2mo,  i  25 

METALLURGY. 

Betts's  Lead  Refining  by  Electrolysis 8vo.  4  oo 

Holland's  Encyclopedia  of  Founding  and  Dictionary  of  Foundry  Terms   Used 

in  the  Practice  of  Moulding 12mo,  3  oo 

Iron  Founder I2mo.  2  50 

Supplement I2mo,  2  50 

Douglas's  Untechnical  Addresses  on  Technical  Subjects I2mo,  i  oo 

Goesel's  Minerals  and  Metals:     A  Reference  Book , . . .  .  i6mo,  mor.  3  oo 

*  Iles's  Lead-smelting 12mo,  2  50 

Keep's  Cast  Iron 8vo,  2  50 

Le  Chatelier's  High-temperature  Measurements.  (Boudouard — Burgess.)  12mo,  3  oo 

Metcalf's  Steel.     A  Manual  for  Steel-users 12mo,  2  oo 

Miller's  Cyanide  Process l2mo  i  oo 

Minet's  Production  of  Aluminum  and  its  Industrial  Use.     (Waldo.)...  .  12mo,  2  50 

Robine  and  Lenglen's  Cyanide  Industry.     (Le  Clerc.) 8vo,  4  oo 

Ruer's  Elements  of  Metallography.     (Mathewson).     (In  Press.) 

Smith's  Materials  of  Machines 12mo,  i  oo 

Thurston's  Materials  of  Engineering.     In  Three  Parts 8vo,  8  oo 

part  I.     Non-metallic  Materials  of  Engineering,  see  Civil  Engineering, 
page  9. 

Part    II.     Iron  and  Steel 8vo,  3  50 

Part  III.     A  Treatise  on  Brasses,  Bronzes,  and  Other  Alloys  and  their 

Constituents 8vo,  2  50 

Ulke's  Modern  Electrolytic  Copper  Refining 8vo,  3  oo 

West's  American  Foundry  Practice I2mo,  2  50 

Moulders  Text  Book 12mo,  2  50 

Wilson's  Chlorination  Process 12mo,  i  50 

Cyanide  Processes 12mo,  i  50 

MINERALOGY. 

Barringer's  Description  of  Minerals  of  Commercial  Value.    Oblong,  morocco,  2  50 

Boyd's  Resources  of  Southwest  Virginia 8vo  3  oo 

Boyd's  Map  of  Southwest  Virginia Pocket-book  form.  2  oo 

*  Browning's  Introduction  to  the  Rarer  Elements 8vo,  i  50 

Brush's  Manual  of  Determinative  Mineralogy.     (Penfield.) 8vo,  4  oo 

Butler's  Pocket  Hand-Book  of  Minerals 16mo,  mor.  3  oo 

Chester's  Catalogue  of  Minerals 8vo,  paper,  i  oo 

Cloth,  i  25 

Crane's  Gold  and  Silver.     (In  Press.) 

Dana's  First  Appendix  to  Dana's  New  "System  of  Mineralogy..*'.  .Large  8vo,  i  oo 

Manual  of  Mineralogy  and  Petrography I2mo  2  oo 

Minerals  and  How  to  Study  Them I2mo,  i  50 

System  of  Mineralogy Large  8vo,  half  leather,  12  50 

Text-book  of  Mineralogy 8vo,  4  oo 

Douglas's  Untechnical  Addresses  on  Technical  Subjects i2mo,  i  oo 

Eakle's  Mineral  Tables - 8vo,  i  25 

Stone  and  Clay  Products  Used  in  Engineering.     (In  Preparation). 

Egleston's  Catalogue  of  Minerals  and  Synonyms 8vo,  2  50 

Goesel's  Minerals  and  Metals :     A  Reference  Book i6mo,  mor.  3  oo 

Groth's  Introduction  to  Chemical  Crystallography  (Marshall)  . I2mo,  i  25 

17 


*Iddings's  Rock  Minerals 8vo,  5  oo 

Johannsen's  Determination  of  Rock-forming  Minerals  in  Thin  Sections 8vo,  4  oo 

*  Martin's  Laboratory  Guide  to  Qualitative  Analysis  with  the  Blowpipe.  i2mo,  60 
Merrill's  Non-metallic  Minerals:  Their  Occurrence  and  Uses 8vo,  4  oo 

Stones  for  Building  and  Decoration 8vo,  5  oo 

*  Penfield's  Notes  on  Determinative  Mineralogy  and  Record  of  Mineral  Tests. 

8vo,  paper,  50 
Tables    of    Minerals,    Including    the  Use  of  Minerals  and  Statistics  of 

Domestic  Production 8vo,  i  oo 

Pirsson's  Rocks  and  Rock  Minerals.     (In  Press.) 

*  Richards's  Synopsis  of  Mineral  Characters I2mo,  mor.  i  25 

*  Ries's  Clays:  Their  Occurrence,  Properties,  and  Uses 8vo,  5  oo 

*  Tollman's  Text-book  of  Important  Minerals  and  Rocks 8vo,  2  oo 

MINING. 

*  Beard's  Mine  Gases  and  Explosions Large  i2mo,  3  oo 

Boyd's  Map  of  Southwest  Virginia Pocket-book  form,  2  oo 

Resources  of  Southwest  Virginia 8vo,  3  oo 

Crane ' s  Gold  and  Silver.     ( I  n  Press.) 

Douglas's  Untechnical  Addresses  on  Technical  Subjects 12010,  I  oo 

Eissler's  Modern  High  Explosives 8ro,  4  oo 

Goesel's  Minerals  and  Metals :     A  Reference  Book i6mo,  mor.  3  oo 

1 1. Iseng's  Manual  of  Mining 8vo,  5  oo 

*  Iles's  Lead-smelting I2mo,  2  50 

Miller's  Cyanide  Process i2mo,  i  oo 

O'Driscoll's  Notes  on  the  Treatment  of  Gold  Ores 8vo,  2  oo 

Peele '  s  Compressed  Air  Plant  for  Mines .     (In  Press. ) 

Riemer's  Shaft  Sinking  Under  Difficult  Conditions.     (Corning  and  Peele) . .  .8vo,  3  oo 

Robine  and  Lenglen's  Cyanide  Industry.     (Le  Clerc.) 8vo,  4  oo 

*  Weaver's  Military  Explosives 8vo,  3  oo 

Wilson's  Chlorination  Process izmo,  i  50 

Cyanide  Processes I2mo,  I  50 

Hydraulic  and  Placer  Mining.     2d  edition,  rewritten i2mo,  2  50 

Treatise  on  Practical  and  Theoretical  Mine  Ventilation 12010,  i  25 

SANITARY  SCIENCE. 

Association  of  State  and  National  Food  and  Dairy  Departments,  Hartford  Meeting, 

1906 8vo,  3  oo 

Jamestown  Meeting,  1907 8vo,  3  oo 

*  Bashore's  Outlines  of  Practical  Sanitation 12mo,  i  25 

Sanitation  of  a  Country  House 12mo,  i  oo 

Sanitation  of  Recreation  Camps  and  Parks 12mo,  i  oo 

Folwell's  Sewerage.  (Designing,  Construction,  and  Maintenance.) 8vo,  3  oo 

Water-supply  Engineering 8vo,  4  oo 

Fowler's  Sewage  Works  Analyses 12m9,  2  oo 

Fuertes's  Water-filtration  Works 12mo,  2  50 

Water  and  Public  Health 12mo,  i  50 

Gerhard's  Guide  to  Sanitary  House-inspection I6mo,  i  oo 

*  Modern  Baths  and  Bath  Houses 8vo,  3  oo 

Sanitation  of  Public  Buildings 12mo,  i  50 

Hazen's  Clean  Water  and  How  to  Get  It Large  12mo,  i  50 

Filtration  of  Public  Water-supplies 8vo,  3  oo 

Kinnicut,  Winslow  and  Pratt 's  Purification  of  Sewage.     (In  Press.) 

Leach's   Inspection   and   Analysis  of  Food  with  Special  Reference  to  State 

Control 8vo,  7  oo 

Mason's  Examination  of  Water.     (Chemical  and  Bacteriological) 12mo,  i  25 

Water-supply.  (Considered  principally  from  a  Sanitary  Standpoint) . .  8vo,  4  oo 
18 


*.Merriman's  Elements  of  Sanitary  Engineering 8vo,    2  oo 

Ogden's  Sewer  Design I2mo,    2  oo 

Parsons's  Disposal  of  Municipal  Refuse 8vo,     2  oo 

Prescott  and  Winslow's  Elements  of  Water  Bacteriology,  with  Special  Refer- 
ence to  Sanitary  Water  Analysis I2mo, 

*  Price's  Handbook  on  Sanitation 12mo, 

Richards's  Cost  of  Food.     A  Study  in  Dietaries 12mo, 


Cost  of  Living  as  Modified  by  Sanitary  Science 12mo, 


So 
50 
oo 
oo 

Cost  of  Shelter 12mo,  oo 

*  Richards  and  Williams's  Dietary  Computer 8vo,  50 

Richards  and   Woodman's  Air,  Water,  and  Food  from  a  Sanitary  Stand- 
point  8vo,  2  oo 

RideaFs  Disinfection  and  the  Preservation  of  Food 8vo,  4  oo 

Sewage  and  Bacterial  Purification  of  Sewage 8vo,  4  oo 

Soper's  Air  and  Ventilation  of  Subways.     (In  Press.) 

Turneaure  and  Russell's  Public  Water-supplies 8vo,  5  oo 

Venable's  Garbage  Crematories  in  America 8vo,  2  oo 

Method  and  Devices  for  Bacterial  Treatment  of  Sewage 8vo,  3  oo 

Ward  and  Whipple '  s  Freshwater  Biology .     ( I  n  Press . ) 

Whipple's  Microscopy  of  Drinking-water 8vo,  3  go 

*  Typhod  Fever Large  12mo,  3  oo 

Value  of  Pure  Water Large  I2mo,  i  oo 

Winton's  Microscopy  of  Vegetable  Foods 8vo,  7  50 

MISCELLANEOUS. 

Emmons's  Geological  Guide-book  of  the  Rocky  Mountain  Excursion  of  the 

International  Congress  of  Geologists Large  8vo,  i  50 

FerrePs  Popular  Treatise  on  the  Winds 8vo,  4  oo 

Fitzgerald's  Boston  Machinist i8mo,  i  oo 

Gannett's  Statistical  Abstract  of  the  World 24mo,  75 

Haines's  American  Railway  Management 12mo,  2  50 

*  Hanusek's  The  Microscopy  of  Technical  Products.    (Winton) 8vo,  5  oo 

Ricketts's  History  of  Rensselaer  Polytechnic  Institute  1 1824-1894. 

Large  i2mo,  3  oo 

Rotherham's  Emphasized  New  Testament Large  8vo,  2  oo 

Standage's  Decoration  of  Wood,  Glass,  Metal,  etc 12mo,  2  oo 

Thome's  Structural  and  Physiological  Botany.    (Bennett) 16mo,  2  25 

Westermaier's  Compendium  of  General  Botany.     (Schneider) 8vo,  2  oo 

Winslow's  Elements  of  Applied  Microscopy 12mo,  i  50 


HEBREW  AND  CHALDEE  TEXT-BOOKS. 

Green's  Elementary  Hebrew  Grammar I2mo,    i  25 

Gesenius's  Hebrew  and  Chaldee  Lexicon  to  the  Old  Testament  Scriptures. 

(Tregelles.) Small  4to,  half  morocco,    5  oo 

19 


14  DAY  USE 

RETURN  TO  DESK  FROM  WHICH  BORROWED 

LOAN  DEPT. 

This  book  is  due  on  the  last  date  stamped  below,  or 

on  the  date  to  which  renewed. 
Renewed  books  are  subject  to  immediate  recall. 


ioOct'6iTD     PEC   819704 


PR  5  •  1978    1 


LD  21A-50m-8,'61 
(Cl795slO)476B 


General  Library 

University  of  California 

Berkeley 


•  '   * 


